Hire Experts For Answers
Order NowRelated Study Services
- Homework Answers
- Coursework writing help
- Term paper writing help
- Writing Help
- Paper Writing Help
- Research paper help
- Thesis Help
- Dissertation Help
- Case study writing service
- Capstone Project Writing Help
- Lab report Writing
- Take my online class
- Take my online exam
- Do my test for me
- Do my homework
- Do my math homework
- Online Assignment Help
- Do my assignment
- Essay Writing Help
- Write my college essay
- Write my essay for me
DESCRIPTION
Posted
Modified
Viewed
20
Methods (sketches of the circuits used, equipment, procedures,).
Results (appropriately annotated and commented on, with appropriate uncertainties)
Ohm's Law(s) - results from the investigation of the resistors, including the table(s), figure(s), and required calculation(s).
Power Law - results from the investigation of the light bulb, including the table(s), figure(s), and the required calculation(s).
Analysis & Discussion (Do the measurements confirm Ohm's law? Do the measurement agreed with the theoretical power law? What can you say about uncertainties in your values? What values did you manage to determine? Did you take enough data...)
Indication of who did what for the lab/report.
PYTHON CODE (uploaded separately)
This order does not have tags, yet.
Attachments
Model 130A/131
Publication Date: June 1984
Document Number: 130A-901-01C
APPLICATIONS DEPT.
mmm
28775 AURORA ROAD
CLEVELAND, OHIO 44139 U.S.A.
1216) 248-0400
WARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in
material and workmanship for a period of two years from date of ship-
ment. During the warranty period, we will, at our option, either repair or
replace any product that proves to be defective.
To exercise this warranty, write or call your local Keithley representative,
or contact Keithley headquarters in Cleveland, Ohio. You will be given
prompt assistance and return instructions. Send the instrument,
transportation prepaid, to the indicated service facility. Repairs will be
made and the instrument returned, transportation prepaid. Repaired
products are warranted for the balance of the original warranty period, or
at least 90 days.
LIMITATION OF WARRANTY
This warranty does not apply to defects resulting from unauthorized
modification or misuse of any product or part. This warranty also does
not apply to fuses, batteries, or damage from battery leakage.
This warranty is in lieu of all other warranties, expressed or implied, in-
cluding any implied warranty of merchantability or fitness for a particular
use. Keithley Instruments, Inc. shall not be liable for any indirect, special
or consequential damages.
STATEMENT OF CALIBRATION
This instrument has been inspected and tested in accordance with
specifications published by Keithley Instruments, Inc.
The accuracy and calibration of this instrument are traceable to the
National Bureau of Standards through equipment which is calibrated at
planned intervals by comparison to certified standards maintained in the
Laboratories of Keithley Instruments, Inc.
S P E C I F I CAT1 0 N S
DC VOLTS
ACCURACY (2 YEARS)
+(%rdg + counts)
RANGE RESOLUTION 1E0-2E0C
200mV 100 pv
2 v 1 mV
200 v 100mV
1000 v 1 v
M A X I M U M ALLOWABLE INPUT: 1OOOV DC or peak AC non-switched,
INPUT RESISTANCE: 10MR.
NORMAL MODE REJECTION RATIO: Greater than 46dB at 50Hz, 60Hz.
COMMON MODE REJECTION RATIO: Greater than lOOdB at DC, 50Hz
AC VOLTS
20 v 10mV +(0.25% + 11
750V peak switched.
and 6OHz (1kQ unbalance].
ACCURACY (2 YEARS)"
f (Yordg + counts) FREQUENCY
RANGE RESOLUTION 1Eo-28OC RANGE
200mV 100 pv
2 v 1 mV
200 v 100mV
750 V 1 v
M A X I M U M ALLOWABLE INPUT: lOOOV peak non-switched, 750V peak
switched: continuous except 200mV range: 15s max above 300V.
INPUT IMPEDANCE: 10MQ shunted by less than 1OOpF.
RESPONSE: Average responding, calibrated in rms of a sine wave.
*Above 10 counts.
OHMS
20 v 10mV + ( l % + 31 45Hz-500Hz
ACCURACY (2 YEARS)
f W r d g + counts) FULL SCALE
RANGE RESOLUTION 1Eo-2E0C VOLTAGE
200 n lOOmn i (O .5% + 4) < 0.5V
2 kQ 1 n * (0.2% + 11 < 0.5V
20 k n 10 n f (0.2% + 1) > 0.7V
200 k f l 100 n f (0.2% + 1) > 0.7V
20MR 10 k f l + ( 2 % + 11 > 0.7V
MAXIMUM OPEN CIRCUIT VOLTAGE: 1.5V.
MAXIMUM ALLOWABLE INPUT: 300V DC or rrns.
DC AMPS
ACCURACY (2 YEARS)
k(%rdg + counts)
RANGE RESOLUTION 18"-28'C
2rnA 1 PA *(0.75% + 1)
20rnA 10 pA +(0.75% + 1)
200rnA 100pA :(0.75% + 1)
2000rnA 1 rnA *(2% + 1)
10 A 10rnA *(2% + 1)
MAXIMUM
FULL SCALE
VOLTAGE
BURDEN
0.25V
0.25V
0.25V
0.7 V
0.3 V
OVERLOAD PROTECTION: rnA input: 2A fuse (250V), externally accessi-
AC AMPS
ble; 10A input: 20A for 15s unfused.
ACCURACY (2 YEARS)' MAXIMUM
*(%rdg + counts) FULL SCALE
18O-28'C VOLTAGE
RANGE RESOLUTION (45HZ-500H~) BURDEN
2rnA 1 PA *(2% + 2) 0.25V
20mA 10 pA * ( 2 % + 2) 0.25V
200rnA 100pA f ( 2 % + 2) 0.25V
2000rnA 1 rnA +(3% + 5) 0.7 V
10 A 10rnA + (3% + 5) 0.3 V
OVERLOAD PROTECTION: rnA input: 2A fuse (250V), externally accessi-
*Above 10 counts.
GENERAL
DISPLAY: 3 % digit LCD, 0.6' height, with polarity and range indication.
OVERRANGE INDICATION: 3 least significant digits blanked.
MAXIMUM COMMON MODE VOLTAGE: 500V peak.
OPERATING ENVIRONMENT: Oo to 5OOC; less than 80% relative humid-
ble; 10A input 20A for 15s unfused.
ity up to 35OC, linearly derate 3% RH/OC from 35OC to 5OOC.
STORAGE ENVIRONMENT: -35OC to 6OOC.
TEMPERATURE COEFFICIENT: (Oo t o 18% and 28O to 50°C): Less than
POWER: 9V alkaline or carbon-zinc battery (NEDA 1604).
BAlTERY LIFE: 100 hours typical with carbon-zinc cells, 200 hours with
0.1 x applicable accuracy specification per OC.
alkaline cells.
BAlTERY INDICATOR: Diplay indicates BAT when less than 10% of life
DIMENSIONS, WEIGHT: 178mm long x 78mm wide x 42mm thick (7.0'
ACCESSORIES SUPPLIED: Batten/, test leads and operating instructions.
remains.
x 3.1" x 1.6')). Net weigth 283gm (10 0 2 . ) .
TABLE OF CONTENTS
General Information
ManualAddenda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preparation for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery Installation/Replacement . . . . . . . . . . . . . . .
Safety Symbols and Terms . . . . . . . . . . . . . . . . . . . .
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Safety Precautions for High Energy Circuits . . . . . . . . . . . . . . . . . 6
Dissassembly Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PartsList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Operation
Servicing Information
GENERAL INFORMATION
The Model 130A Digital Multimeter is supplied ready for use with a bat-
tery. Descriptions of other available accessories, and other general in-
formation concerning the instrument can be found below.
MANUAL ADDENDA
Information contained in this manual is believed to be accurate at the
time of printing. Any improvements or changes to this manual will be
documented in an addendum which will be included with the, instru-
ment.
OPTIONAL ACCESSORIES
Model 1301 Temperature Probe is a rugged low cost temperature
probe designed to allow precision temperature measurement from
Model 1304 Soft Carrying Case and Stand
Model 1306 Deluxe Case is a rugged DMM carrying case that is large
enough to accomodate the Model 130A plus various other DMM articles
such as a spare battery, test leads, etc.
Model 1309 Spare Parts Kit is a collection of specially selected parts
to maintain up to ten Model 130A DMMs for one year.
Model 1600A High Voltage Probe extends the DMM to 40kV. It has a
1OOO:l division ratio, which means that 1V on the DMM corresponds to
1 kV.
Model 1651 50-Ampere Shunt allows current measurements to be
made up to 50-amperes. It is a 0.0010 1 % Cterminal shunt. When the
DMM is set to the 2V range, a 50-ampere current will correspond to
50mV (.0500V).
Model 1681 Clip-On Test Lead Set contains two leads, 1.2m(48 inch-
es) long, terminated with banana plug and spring action clip-on probe.
Model 1682A RF Probe allows voltage measurements from 100kHz to
250MHz.
Model 1683 Universal Test Lead Kit consists of two test leads, 1.2177
(48 inches) long with 12 screw-in tips, two banana plugs, two spade
lugs, two alligator clips with boots, two needle tips with chucks and
four heavy-duty tip plugs.
-55OC to 150OC.
1
Model 1685 Clamp-On AC Current Probe measures AC current by
clamping onto a single conductor. Interruption of the current path is un-
necessary. The Model 1685 detects current by sensing magnetic field
produced by current.
Model 1691 General Purpose Test Lead Set consists of two .91m (36
inches) test leads with probe tips terminated in banana plugs.
PREPARATION FOR USE
Carefully unpack the Model 130A from its shipping carton and inspect
for any obvious signs of physical damage. Report any damage to the
shipping agent at once. The following items are included with every
Model 130A shipment.
1. Model 130A DMM
2. Model 130A Instruction Manual
3. 9V Battery NEDA 1604
4. Test Leads
5. Accessories as ordered.
BATTERY INSTALLATION/REPLACEMENT
The battery is accessible from the bottom of the instrument. Note the
precautions on the case before installing or replacing the battery.
WARNING
Turn the Model 130A off and disconnect test
leads before replacing the battery. Put the cover
back into place on the compartment before
resuming use of the instrument.
A 9V battery is supplied with the instrument but not installed. To install
or replace the battery, remove the cover from the battery compartment
by sliding it off in the direction of the arrow located on the battery
cover. The battery connector snaps on and off the terminal of the bat-
tery. Improper installation of the battery will cause the connecting wires
to be severed by excess strain. Proper installation requires that the bat-
tery be positioned in such a manner (see drawing) that the leads pro-
truding from the boot of the battery connector face toward the outside
of the battery compartment. If the instrument is going to be stored for a
long period of time or in a high temperature environment, remove the
battery to prevent leakage damage.
2
R103
Figure 1. Battery Installation
SAFETY SYMBOLS AND TERMS
The symbol A on the instrument denotes that the user should refer
to the operating instructions.
The symbol r / on the instrument denotes that up to lOOOV may be
present on the terminal(s).
The WARNING used in this manual explains dangers that could result
in personal injury or death.
The CAUTION used in this manual explains hazards that could damage
the instrument.
3
SAFETY PRECAUTIONS
The following safety precautions should be observed before operating
the Model 130A DMM.
1 . This instrument is intended for use by qualified personnel who
recognize shock hazards and are familiar with the safety precautions
required to avoid possible injury. Read over the manual carefully
before operating this instrument.
2. Exercise extreme caution when a shock hazard is present at the in-
strument's input. The American National Standards Institute (ANSI)
states that a shock hazard exists when voltage levels greater than
30V rms or 42.4V peak are present. A good safety practice is to ex-
pect that a hazardous voltage is present in any unknown circuit
before measuring.
3. Inspect the test leads for possible wear, cracks or breaks before each
use. If any defects are found, replace with test leads that have the
same measure of safety as those supplied with the instrument.
4. For optimum safety do not touch the test leads or the instrument
while power is applied to the circuit under test. Turn the power off
and discharge all capacitors, before connecting or disconnecting the
instrument.
5. Do not touch any objects which could provide a current path to the
common side of the circuit under test or power line (earth) ground.
Always make measurements with dry hands while standing on a dry,
insulated surface, capable of withstanding the voltage being
measured.
6. Exercise extreme safety when testing high energy power circuits (AC
line of mains, etc.). Refer to the operation section.
7. Do not exceed the instrument's maximum allowable input as defined
in the specifications and operation section.
4
OPERATION
The following paragraphs contain information concerning basic opera-
tion of the Model 130A. It is recommended that this information be
reviewed before attempting to operate the Model 130A.
Low Battery Indicator
Minus sign indicates negative
values. Plus sign implied. An over
range condition is indicated by a “1“
followed by a blank display.
‘SET POWER ON (slide switch
located on side of instrument).
ELECT FUNCTION A N D fl RANGE
DCV-20OmV, 2V, 20V, 200V or
1 ooov
ACV-200mV, 2V, 20V, 200V, or
1 ooov
NOTE: 750VAC is maximum
allowable AC input.
DCA-2mA, 20mA, 200mA,
2000mA or 10A
ACA-2mA, 20mA, 200mA,
2000mA or 10A
0-2003, 2k0, 20k0, 200kR or
20M0
-INPUTS-Selects appropriate pair
of input jacks.
COM, V-0-for all voltage and
resistance measurements.
COM, mA-for current measure-
ments up to 2000mA.
10A, COM, 10A, HI-for current
measurements up to 10A.
Figure 2. Front Panel Controls
WARNING
Do not apply more than 500V peak above earth
ground to the COM input jack.
5
CAUTION
Do not under any circumstance, use the 10A
COM or 10A HI input jacks with the COM input
jack for making measurements. This is a short
and will damage the instrument.
SAFETY PRECAUTIONS FOR HIGH ENERGY CIRCUITS
To optimize safety when measuring voltage in high energy distribution
circuits, read and use the directions in the following warning.
WARNING
Dangerous arcs of an explosive nature in a high
energy circuit can cause severe personal injury or
death. If the meter is connected to a high energy
circuit, when set t o a current range, low
resistance range or any other low impedance
range, the circuit is virtually shorted. Dangerous
arcing can result even when the meter is set to a
voltage range if the minimum safety spacing is
reduced.
When making measurements in high energy circuits use test leads that
meet the following requirements:
1. Test leads should be fully insulated.
2. Only use test leads than can be connected to the circuit (e.g.
alligator or spade plugs) for a hands-off measurement.
3. Use test leads that do not reduce the arc protection by decreasing
the voltage spacing.
Use the following sequence when testing power circuits:
1. De-energize the circuit using the regular installed connect-
disconnect device such as the circuit breaker, main switch, etc.
2. Attach the test leads to the circuit under test. Use appropriate safety
rated leads for this application.
3. Set the DMM to thg proper function and range.
4. Energize the circuit using the installed connect-disconnect device
and make measurements without disconnecting the DMM.
5. De-energize the circuit using the installed connect-disconnect
device.
6. Disconnct the test leads from the circuit under test.
6
SERVICING INFORMATION
This section contains servicing information for the Model 130A.
WARNING
All service information is intended for qualified
electronic maintenance personnel only.
FUSE CHECK
With the instrument set to the 2kQ range, connect a jumper from the
V-Q jack to the mA jack. The display should read approximately .loo.
An overrange display would typically indicate a blown fuse. A display
reading other than approximately .lo0 could indicate a defective current
input circuit (see schematic).
FUSE REPLACEMENT
A 2-amp fuse protects the 2mA through 2000mA current ranges. To
gain access to the fuse, remove the fuse Compartment cover in the
same manner as removing the battery compartment cover.
WARNING
Turn off the Model 130A and disconnect the test
leads before replacing the fuse. Reinstall fuse
compartment cover before attempting to
operate the instrument.
Remove the fuse by pulling outward on the plastic tab that encircles the
fuse body. Install the plastic tab on the new fuse and snap the fuse back
into the fuse holder. Do not replace the fuse with a higher rated value or
instrument damage that is not covered by the warranty may occur.
DIODE TEST
The 20kQ range can be used for testing of semiconductor junctions. A
junction is probably good if the Model 130A indicates an overrange
reading when the semiconductor is reversed biased, and an on-range
reading, when the semiconductor is forward biased. (The V-fl jack is
positive).
7
DISASSEMBLY INSTRUCTIONS
Place the unit face down on a bench or other similar surface and remove
the battery compartment cover. Disconnect and remove the battery.
Remove the two #4-40 X 7/8 retaining screws.
Grasp the bottom cover at the input jack end and with a lifting and for-
ward pushing motion (see drawing), carefully remove the bottom cover.
While removing the cover, feed the battery connector through the ac-
cess hole in the bottom of the battery compartment.
The component side of the PC board is now exposed and the battery
can be reconnected for troubleshooting. To read the display, some light
downward pressure at the top of the circuit board may be required in
order to make contact through the elastomer contact strip between the
circuit board and the LCD.
The PC board and LCD assembly are not secured once the case retain-
ing screws are removed. Be careful not to allow the PC board and LCD
assembly to fall out or shift out of position during calibration.
To remove the PC board from the top cover, grasp the function switch
assembly and lift until the input jacks become disengaged from the
cover. The PC board can now be removed using a slight clockwise mo-
tion to free the two switch knobs from their normal positions in the
case.
The LCD assembly will remain in the top cover when the PC board is
removed. Again, be careful not to allow the LCD assembly to fall out ac-
cidentally.
The two switch knobs and bushings can be removed from the PC board
assembly by simply pulling them off the switch shafts.
The LCD assembly, along with the zebra strip connector, lifts out of the
case.
To reassemble the Model 130A, remove the cover on the fuse cornpart-
ment (to position fuse pulling tab) and reverse the above procedures.
Be sure to replace the on-off switch cover. Common-mode voltage will
be present on the switch, creating a possible hazard if the cover is not
replaced.
8
1 t
PUSH
FORWARD
! LIFT
c-- , I
I I
I I
Figure 3. Rear Panel Removal
TOP CASE
Figure 4. Model 130A Exploded View
9
CALI BRATION
Calibration should be performed every two years or whenever the in-
strument is known to be out of specification. Calibration should be done
at an ambient temperature of 23O f3OC ( 7 7 O f5OF), with a relative
humidity of less than 80%.
Equipment Needed: + 190mV DC voltage source with -05% accuracy
or better.
Model 130A Settings: DCV function, 200mV range, V-s2 and COM input
jacks.
CALIBRATION PROCEDURE
Remove the battery cover to gain access to the calibration pot R103 (see
Figure 1). Apply the + 190mV to the Model 130A input and adjust R103
for a display reading of 190.0 f 1 digit. This is the only adjustment need-
ed to calibrate the instrument. Calibration should be performed every
two years.
10
Model 130A Parts List
Circuit
Deslg.
BT101
c101
c102
C103
C104
C105
C106
C107
C108
c109
c110
c111
c112
C113
CR101
CR102
CR103
CR104
CR105
CR106
CR107
CR108
CR109
DS101
F101
J1001
J 1002
J 1003
J1004
J1005
J1006
Q101
Q102
R101
R102
R103
R104
R105
R106
R107
Description
Battery, 9V, NEDA 1604
Capacitor, 1 lOpF, 500V, Mica
Capacitor, .047pF, lOOV, Polyester
Capacitor, .047pF, lOOV, Polyester
Capacitor, .IFF, lOOV, Polyester
Capacitor, .lpF, 16OV, Polypropylene
Capacitor, 1.5pF, 20V, Tantalum
Capacitor, 4.7pF, 20V, Tantalum
Capacitor, 1 .5pF, 20V, Tantalum
Capacitor, .02pF, lOOOV, Ceramic
Disc
Capacitor, .IFF, 50V, Ceramic
Capacitor, .1pF, 50V, Ceramic
Capacitor, lpF, 20V, Tantalum
Capacitor, 4.7pF, 20V, Tantalum
Rectifier, lA, 800V
Rectifier, 75mA, 75V
Rectifier, 75mA, 75V
Rectifier, 75mA, 75V
Rectifier, 75mA, 75V
Rectifier, 75mA, 75V
Rectifier, 3A, 50V
Rectifier, 3A, 50V
Rectifier, 75mA, 75V
Liquid Crystal Display
Connector, Strip
Fuse, 2A, 250V, 3AB, Ceramic Body
Jack, Input
Jack, Input
Jack, Input
Jack, Input
Jack, Input
Connector Battery
Transistor, NPN, Switch, 2N3904
Transistor, NPN, Silicon, GES5818
Thick Film Resistor Network
Thick Film Resistor Network
Pot, 500Q
Thick Film Resistor Network
Resistor, lMQ, lo%, lW, Comp
Resistor, .lo, .5%, lW, WW
NOT USFD
-
Sch
LOC
c4
H3
F3
E4
G3
G3
04
D2
D4
c2
c2
D2
D2
F1
c4
C6
c2
c2
D2
D2
A4
84
83
G5
A4
A1
A4
A4
85
85
c4
E5
E3
SEV
SEV
G2
B3,B4
E4
84
-
Keithley
Pert No.
BA-14
C-320-11OP
C-308.047
C-305,047
C-305.1
C-306.1
C-3141.5
C-314-4.7
C-314-1.5
C-316.02
C-238.1
C-238.1
C-3251
C-3194. I
R F-38
RF-28
RF-28
RF-28
RF-28
RF-28
RF-34
RF-34
RF-28
DD-27
CS-3762
FU-62
130A-303
130A-303
13OA-303
130A-303
130A-303
BH-29
TG-47
TG-138
TF-97
TF-119
RP-119-500
TF-94
R-2-1M
R-279.1
11
Model 130A Parts List (Cont.)
Circuit
Desig.
R108
R109
R110
R111
R112"
R113
R114
R115
R116
R117
R118
R119
R120
R121
R122"
R123"
4T101
s101
s102
S103
u101
u102
U103
VRlOl
~~ ~~
lescription
aesistor, 1000, .1%, 1/1OW, MtF
Resistor, 9000, . l%, l/ lOW, MtF
Resistor, 9k0, , l%, 1/1OW, MtF
Resistor, 90k0, . l%, l/ lOW, MtF
Resistor, 900k0, . l%, 1/1OW, MtF
Resistor, 100k0, lo%, lW, Comp
NOT USED
Resistor, 4.72k0, . l%, 1/1OW, MtF
Resistor, 10k0, , l%, l/ lOW, MtF
Thick Film Resistor Network
Resistor, 0.010, 0.5%, lW, WW
NOT USED
NOT USED
NOT USED
Resistor, 9M0, .08%, 2W
Thick Film Resistor Network
Thermistor, 8mA, 500V, PTC
Switch, SPDT, ON-OFF
Switch, Rotary, Range
Switch, Rotary, Function
3 1/2-Digit Single Chip A/D
Converter
CMOS Quad Exclusive OR Gate
Low-Power JFet-Input OP-Amp
Diode, Low Voltage Reference
Supplied Test Lead Set
Sch
LOC
83
82
B2
82
82
c1
-
D3
02
S EV
B5
81
B1
E2
c4
S EV
E2, F2
G4
F5, F6
c2
G1
~
"R123 may be installed in your unit in place of R122 and R1
configuration).
ALTERNATE CONFIGURATION
Keithley
Part No.
R-283-100
R-283-900
R-283-9k
R-283-90k
R-283-900k
R-2- 1 OOk
R-283-4.71 k
R-283-10k
TF-96
R-280-.01
R-281-9M
TF-104
RT-7
SW-417
SW-432
sw-433
32440
30847
IC-227
DZ-62
CA-8
(see alternate
12
COMPONENT LAYOUT
13
SCHEMATIC DIAGRAM
INPUT $'"
I
I
15
SERVICE FORM
Model No.
Name Phone
Company
Address
City State Zip
Serial No. ~ P.O. No. date
List all control settings and describe problem.
(Attach additional sheets as necessary. 1
Show a block diagram of your measurement system including all instruments connected (whether power
is turned on or notl. Also describe signal source.
Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.1-
What power line voltage is used?
Variation? O F . Rel. Humidity? Other?
Variation?
Frequency? Ambient Temperature? OF.
Any additional information (If special modifications have been made by the user, please describe below 1
‘Be sure to Include your name and phone number an this sewice form
Keithlsy Instruments. lnc./28775 Aurora RoadiCleveiand, Ohio 44139/U.S.A./(2161 2484400/Teiex: 985469
WEST GERMANY: Keithlsy Inatruments GmbH/Heiglhofstrasse 5/D-8000 Munchen 70/314 289/Telex: 1345000
GREAT BRITAIN: Keithlsy Instrurnenta. Ltd./l, Boulton RoadiReading, Berkshire RG2 ONL110734) 88 12 87/Telex: 847047
FRANCE: Keithlsy Instruments SARL/2 Bis, Rue LBon Blum/B.P. 60/91121 Palaiseau Cedexll61 0115 155/Telex: 600933
NETHERLANDS: Keithley lnatrumentr BV/Arkelsedijk 4/NL4206 AC Gorinchem/(01830l 25577/Telex: 24 684
SWITZERLAND: Keithlsy Inatruments SAIKriesbachstr. 4/CH-8660 DubendorfiOl 821 94 44/Telex: 57 536
AUSTRIA: Keithley Instruments Gss.m.b.H/Doblinger Hauptstr. 32/A-1190 Wien/0222 314 289/Telex: 134500
Find us at www.keysight.com Page 1
U1270 Series Handheld Digital Multimeters
Be Ready for Harsh Environments and Sub-zero Temperatures
The U1273AX, the latest addition to the U1270 Series is capable of operating down
to –40 °C in temperature. Even in extremely cold conditions, the U1273AX handheld
DMM delivers immediate and accurate results — no warm-up time required.
All models are ergonomically built providing useful functions such as ZLOW, which
eliminates stray voltages, and Smart Ohm that minimizes false readings from
residual voltage induced by leakage current. All of this is designed into a case that
fulfills the needs of today's industrial handheld users.
Find us at www.keysight.com Page 2
Features
– OLED display with 2000:1 contrast ratio and 160 degrees viewing angle3,4
– 30,000-count resolution
– Measure up to 1000 V AC and DC
– Measure up to 10 A (20 A for 30 s)
– Resistance, diode test, temperature, capacitance
– Low Impedance mode2,3,4 and Low Pass Filter
– Peak detection of up to 250 µs
– Continuity test with beeper and backlight1,2
– Seven readings/s measurement rate for voltage and current
– Smooth function for accurately stable readings
– Up to 10,000 points internal memory for data logging
– Bluetooth wireless connectivity with optional U1177A Bluetooth
– PC connectivity with optional U1173A IR-USB cable
– IP 54 certified – water and dust resistant
– CAT III 1000 V, CAT IV 600 V safety rating
– Up to 3000m operating altitude
– –40 to 55 °C operating temperature4
1. U1271A
2. U1272A
3. U1273A
4. U1273AX
Operational down to –40 °C temperature
The U1273AX OLED handheld digital multimeter, the latest addition to U1270 Series, is capable of operating
in winter weather down to –40°C temperature. Even in frigid conditions, the U1273AX enables you to achieve
immediate and accurate results without the need to warm up in advance.
Increase productivity with Bluetooth® wireless connectivity
For wireless connectivity to smartphones and tablets, the U1270 Series is compatible with the U1177A
infrared-to-Bluetooth adapter for maximum efficiency and productivity in completing measurements tasks.
Adding the optional U1177A to a U1270 Series you can easily perform remote monitoring and data logging
via Android devices or Windows- based PC.
OLED for more display clarity
Designed with OLED display, you can experience crystal-clear measurement readings with its outstanding
2000:1 contrast ratio. The display also allows wider viewing angles up to 160 degrees ensuring you get the
right readings at the first glance even in poorly lit environments.
Find us at www.keysight.com Page 3
Features
Water and dust resistance (IP54)
The series’ tightly sealed design helps protect against water, dust and damage. Each handheld DMM is
certified with IP 54 ratings so that you can carry out tests and measurements with confidence, even in harsh
working conditions.
Operational up to 3000 meters altitude
For high altitude applications such as wind farm maintenance, you can measure with confidence using the
U1270 Series, capable of measuring up to 3000 meters above sea level.
High measurement rate at seven readings per second for Voltage and Current
You can detect even the slightest change in your sensitive signals (Voltage and Current) with its high
measurement rate capability. By clicking the resettable smooth function button, you may customize the
readings’ sensitivity suitable for various tests.
Visual alert for continuity test (for U1271A and U1272A only)
Continuity detection in noisy and dark environments is made easy with U1270 Series’ loud beeper and
flashing backlight that indicates continuity and thus improves safety.
Up to 10,000 recording points for manual, auto and event logging
Record measurements on-the-go and transfer data to PC conveniently with the huge internal memory of up
to 10,000 recording points. The GUI Data Logging software and optional U1173A IR-USB cable are required
to transfer data or perform real time data logging on a PC.
Built-in Low Pass Filter
The U1270 Series offers a 1 kHz LPF or Low Pass Filter to provide accurate Variable Frequency Drive
(VFD) output measurements. This function eliminates high frequency noise and harmonics, ensuring motor
filter efficiency.
Figure 1. Comparison of voltage output from industrial motor VFD without and with Low Pass Filter
functionality.
Key Functions
Key Functions
Find us at www.keysight.com Page 4
Low impedance mode
Stray voltages are usually found in non-energized electrical wiring adjacent to powered wires due to
capacitive or inductive coupling between these wires. The low impedance mode serves to eliminate false
readings by dissipating these stray voltages thus improves safety and measurement efficiency during voltage
measurement.
Peak detect at 250 µs
The peak detect function allows you to capture the engine or motor startup transient as fast as 250 µs.
Figure 2. U1272A helps you identify the presence of stray voltage on a disconnected wire running parallel
with the wire powering up the VFD to an industrial motor. The image on the right shows the U1272A in low
impedance mode.
Find us at www.keysight.com Page 5
Front and Back Panel Description
1. U1272A, U1273A and
U1273AX only
Front Panel
Figure 3. Once connected to any HH DMM via Bluetooth adapter you are able to log and
view measurements graphically from smart phones and tablets.
Peak detect records
transients as fast as 250 μs
Measure up to 1000V
AC and DC
Low Pass Filter (LPF)
removes unwanted high
frequency signals
ZLOW1provides both high
and low impedance modes
to eliminate stray voltages
Smart Ω 1 removes residual
voltage of up to 1000 mV
30,000 counts resolution
OLED display with 2000:1
contrast ratio and 160
degree viewing angle
Auto diode 1 automatically
determines diode polarity
Temperature measurement:
J type thermocouple
–210 to 1200 °C 1, K type
thermocouple –200 to 1732 °C
Measure up to 10 A
(20 A for 30 s)
Front and Back Panel Description
Find us at www.keysight.com Page 6
Back Panel
Hang hole
Probe holder/storage
IR-USB connectivity with
optional IR-USB cable
Slim, ergonomic design
for better grip
Easy fuse and
battery access from
battery cover
beneath the stand
Choose Among These Four Models
Find us at www.keysight.com Page 7
Basic Features
U1271A U1272A U1273A U1273AX
Display
resolution
30,000 counts 30,000 counts 30,000 counts 30,000 counts
Display LCD LCD OLED OLED
Backlight Yes Yes N/A N/A
True RMS AC AC + DC AC + DC AC + DC
Measurements
Voltage Up to 1000 V AC, DC Up to 1000 V AC, DC Up to 1000 V AC, DC Up to 1000 V AC, DC
Basic dcV
accuracy
0.05% + 2 counts 0.05% + 2 counts 0.05% + 2 counts 0.05% + 2 counts
Current Up to 10 A Up to 10 A Up to 10 A Up to 10 A
(20 A for 30 s) (20 A for 30 s) (20 A for 30 s) (20 A for 30 s)
Resistance Up to 100 MΩ Up to 300 MΩ Up to 300 MΩ Up to 300 MΩ
Other
measurements
Frequency,
capacitance,
temperature,
continuity,
diode test
Frequency,
capacitance,
temperature,
continuity,
diode test
Frequency,
capacitance,
temperature,
continuity,
diode test
Frequency,
capacitance,
temperature,
continuity,
diode test
AC bandwidth 20 kHz 100 kHz 100 kHz 100 kHz
Low pass filter Yes Yes Yes Yes
Low impedance
mode
— Yes Yes Yes
Smart Ohm — Yes Yes Yes
Safety and Regulatory
Over-voltage
safety protection
CAT III 1000 V,
CAT IV 600 V
CAT III 1000 V,
CAT IV 600 V
CAT III 1000 V,
CAT IV 600 V
CAT III 1000 V,
CAT IV 600 V
General
Logging memory 200 points 10,000 points 10,000 points 10,000 points
Connectivity Optional IR-USB and
Bluetooth
Optional IR-USB and
Bluetooth
Optional IR-USB and
Bluetooth
Optional IR-USB and
Bluetooth
Operating
temperature
–20 to 55 °C –20 to 55 °C –20 to 55 °C –40 to 55 °C
Altitude 3000 meters 3000 meters 3000 meters 3000 meters
Water and dust
ingress protection
IP 54 IP 54 IP 54 IP 54
Battery life Up to 300 hours 4X
AAA Alkaline
Up to 300 hours 4X
AAA Alkaline
Up to 60 hours 4X
AAA Alkaline
Up to 100 hours 4X
AAA Lithium
General Specifications (continued)
Find us at www.keysight.com Page 8
Display U1271A and U1272A: Liquid crystal display (LCD) (with maximum reading of 33,000
counts)
U1273A/U1273AX: Organic LED (OLED) display (with maximum reading of 33,000
counts)
(Note: OLED is made of organic materials and it has its lifespan.)
Power
consumption
U1271A/U1272A: 460 mVA maximum (with backlight enabled)
U1273A/U1273AX: 180 mVA maximum (with maximum brightness)
Battery type 4 × 1.5 V Alkaline battery (ANSI/NEDA 24A or IEC LR03), or
4 × 1.5 V Zinc Chloride battery (ANSI/NEDA 24D or IEC R03)
4 × 1.5 V Lithium battery (ANSI/NEDA 24LF or IEC FR03)
Battery life U1271A and U1272A: 300 hours typical (based on new Alkaline batteries for DC
voltage measurement)
U1273A/U1273AX:
Based on new Alkaline batteries for DC voltage measurement:
30/45/60 hours typical at High/Medium/Low brightness, respectively
Based on new Lithium batteries for DC voltage measurement:
50/100 hours typical at High/Low brightness, respectively
Low battery indicator will flash when the battery voltage drops:
For non-rechargeable batteries: 4.4 V (approximately)
For rechargeable batteries: 4.5 V (approximately)
Fuse 10 × 35 mm 440 mA/1000 V 30 kA fast-acting fuse
10 × 38 mm 11 A/1000 V 30 kA fast-acting fuse
Input impedance
at off mode
1.67 kΩ (protected by positive temperature coefficient resistor)
(U1272A, U1273A and U1273AX only)
Operating
environment
Operating temperature:
U1271A/ U1272A/U1273A: –20 to 55 °C, 0% to 80% RH
U1273AX: –40 to 55 °C, 0% to 80% RH (using Lithium batteries)
Full accuracy up to 80% RH for temperatures up to 30 °C, decreasing linearly to 50% RH
at 55 °C
Altitude up to 3000 meters
Pollution degree II
Safety
compliance
–40 to 70 °C, 0 to 80% RH
Storage
compliance
IEC 61010-1:2010 / EN 61010-1:2010, IEC 61010-2-033:2012 / EN 61010-2-
033:2012 Canada: CAN/CSA-C22.2 No.61010-1-12, CAN/CSA-C22.2 No. 61010-2-
033-12
USA: ANSI/UL Std. No. 61010-1 (3rd Edition), ANSI/UL Std. No. 61010-2-033 (1st Edition)
Measurement
category
CAT III 1000 V/CAT IV 600 V
General Specifications (continued)
Find us at www.keysight.com Page 9
Electromagnetic
compatibility
(EMC)
Commercial limits compliance with EN61326-1
Influence of radiated immunity; in RF electromagnetic fields of 3 V/m
DC voltage measurement typical accuracy
All ranges; ± 0.03% of range
DC current measurement typical accuracy
300 uA, 3000 uA, 30 mA, 300 mA & 3 A range; ± 0.22% of range
10 A range; ± 0.66% of range
Note:
– The measurement accuracy is applied only when DC Low Pass Filter (LPF) is
ON (factory default).
– The use of LPF is recommended to improve the accuracy of measurements in
the presence of RF fields.
If used in close proximity to an RF transmitter or when subjected to continuously
present electromagnetic phenomena, some recoverable degradation of performance
may occur.
Ingress protection
rating
IP-54
Temperature
coefficient
U1271A/U1272A/U1273A: 0.05 × (specified accuracy)/°C (from –20 to 18 °C, or 28 to 55 °C)
U1273AX: 0.05 x (specified accuracy/ °C (from –40 to 18 °C, or 28 to 55 °C)
Common Mode
Rejection Ratio
(CMRR)
> 120 dB at DC, 50/60 Hz ± 0.1% (1 kΩ unbalanced)
Normal Mode
Rejection Ration
(NMRR)
> 60 dB at 50/60 Hz ± 0.1%
Dimensions (W x
H x D)
92 × 207 × 59 mm
Weight U1271A: 518 grams (with batteries)
U1272A: 520 grams (with batteries)
U1273A: 500 grams (with batteries)
U1273AX: 500 grams (with batteries)
Calibration cycle One year
Specification Assumptions
• Accuracy is given as ± (% of reading + counts of least significant digit) at 23 °C ± 5 °C, with relative
humidity less than 80% RH.
• AC V and AC μA/mA/A specifications are AC coupled, true RMS and are valid from 5% of range to 100% of
range.
• Crest factor ≤ 3 at full-scale and decrease reciprocally for overange as 3 x Full Scale / Input; except for the
1000 V range, where this range has a crest factor ≤ 1.5 at full scale and decrease reciprocally for overange
as
1.5 x Full Scale / Input.
• For non-sinusoidal waveforms, add (2% of reading + 2% of full scale) typical.
• After ZLOW voltage measurements, wait at least 20 minutes for thermal impact to cool before proceeding with
any other measurement.
Electrical Specifications
Find us at www.keysight.com Page 10
DC specifications for U1271A, U1272A, U1273A and U1273AX
Function Range Resolution Accuracy ± (% of reading + counts of least significant digit)
Test current /
Burden voltage
U1271A U1272A U1273A / U1273AX
Voltage1
30 mV 0.001 mV — 0.05 + 20 0.05 + 20 —
300 mV 0.01 mV 0.05 + 5 0.05 + 5 0.05 + 5 —
3 V 0.0001 V 0.05 + 5 0.05 + 5 0.05 + 5 —
30 V 0.001 V 0.05 + 2 0.05 + 2 0.05 + 2 —
300 V 0.01 V 0.05 + 2 0.05 + 2 0.05 + 2 —
1000 V 0.1 V 0.05 + 2 0.05 + 2 0.05 + 2 —
ZLOW (low
impedance)
enabled,
applicable
for 1000 V
range and
resolution
only
0.1 V
—
1 + 20
1 + 20
—
Resistance2
30 Ω 0.001 Ω — 0.2 + 10 0.2 + 10 0.65 mA
300 Ω 0.01 Ω 0.2 + 5 0.2 + 5 0.2 + 5 0.65 mA
3 kΩ 0.0001 kΩ 0.2 + 5 0.2 + 5 0.2 + 5 65 µA
30 kΩ 0.001 kΩ 0.2 + 5 0.2 + 5 0.2 + 5 6.5 µA
300 kΩ 0.01 kΩ 0.2 + 5 0.2 + 5 0.2 + 5 0.65 µA
3 MΩ 0.0001 MΩ 0.6 + 5 0.6 + 5 0.6 + 5 93 nA/10 MΩ
30 MΩ 0.001 MΩ 1.2 + 5 1.2 + 5 1.2 + 5 93 nA/10 MΩ
100 MΩ 0.01 MΩ 2.0 +10 — — 93 nA/10 MΩ
300 MΩ 0.01 MΩ —
2.0 + 10 @ < 100 MΩ
8.0 + 10 @ > 100 MΩ
2.0 + 10 @ < 100 MΩ
8.0 + 10 @ > 100 MΩ 93 nA/10 MΩ
300 nS 0.01 nS 1 + 10 1 + 10 1 + 10 93 nA/10 MΩ
Current3
300 µA 0.01 µA 0.2 + 5 0.2 + 5 0.2 + 5 < 0.04 V/100Ω
3000 µA 0.1 µA 0.2 + 5 0.2 + 5 0.2 + 5 < 0.4 V/100 Ω
30 mA 0.001 mA 0.2 + 5 0.2 + 5 0.2 + 5 < 0.08 V/1 Ω
300 mA 0.01 mA 0.2 + 5 0.2 + 5 0.2 + 5 < 1.00 V/1 Ω
3 A 0.0001 A 0.3 + 10 0.3 + 10 0.3 + 10 < 0.1 V/0.01 Ω
10 A 0.001 A 0.3 + 10 0.3 + 10 0.3 + 10 < 0.3 V/0.01 Ω
Diode Test4
3 V 0.0001 V 0.5 + 5 0.5 + 5 0.5 + 5 Approximately
1 to 2 mA
Auto 0.0001 V — 0.5 + 5 0.5 + 5 Approximately
1 to 2 mA
Electrical Specifications (continued)
Find us at www.keysight.com Page 11
Notes for DC specifications (previous page)
1. Notes for voltage specifications:
The accuracy of the 30 to 300 mV range is specified after the Null function is used to subtract the
thermal effect (by shorting the test leads).
ZLow impedance: 2 kOhm (nominal). For ZLow measurements, autoranging is disabled and the
multimeter's range is set to 1000 volts in the manual ranging mode.
2. Notes for resistance specifications:
Overload protection: 1000 Vrms for short circuits with < 0.3 A current.
Maximum open voltage is < +3.3 V.
Built-in buzzer beeps when the resistance measured is less than 25 Ω ± 10 Ω. The multimeter can
capture intermittent measurements longer than 1 ms.
U1272A/73A/73AX only: The accuracy of the 30 Ω to 3 kΩ range is specified after the Null function is
used to subtract the test lead resistance and thermal effect (by shorting the test leads).
U1271A only: The accuracy of the 300 Ω to 3 kΩ range is specified after the Null function is used to
subtract the test lead resistance and thermal effect (by shorting the test leads).
U1273AX only: The accuracy for all resistance ranges is specified after the Null function is used when
measuring at temperatures below –20 °C. The Null function is used to subtract the test lead resistance
and thermal effect (by shorting the test leads).
For the ranges of 30 MΩ and 100 MΩ, the RH is specified for < 60%.
The accuracy for ranges < 50 nS is specified after the Null function is used on an open test lead.
The temperature coefficient of the 100 MΩ and 300 MΩ range is 0.1 × (specified accuracy)/°C (from –40
to 18 °C or 28 to 55 °C).
3. Notes for current specifications:
Overload protection for 300 μA to 300 mA range: 0.44 A/1000 V; 10 × 35 mm 30 kA fast-acting fuse.
Overload protection for 3 A to 10 A range: 11 A/1000 V; 10 × 38 mm 30 kA fast-acting fuse.
Specification for 300 mA range: 440 mA continuous.
Specification for 10 A range: 10 A continuous. Add 0.3% to the specified accuracy when measuring
signals > 10 to 20 A for 30 seconds maximum. After measuring currents > 10 A, cool down the
multimeter for twice the duration of the measured time before proceeding with low current
measurements.
4. Notes for diode specifications:
Overload protection: 1000 Vrms for short circuits with < 0.3 A current.
Built-in buzzer beeps continuously when the voltage measured is less than 50 mV and beeps once for
forward-biased diode or semiconductor junctions measured between 0.3 V and 0.8 V (0.3 V ≤ reading
≤ 0.8 V).
Open voltage for diode: < +3.3 V DC.
Open voltage for Auto diode: < +2.5 V DC and > –1.0 V DC.
Electrical Specifications (continued)
Find us at www.keysight.com Page 12
AC specifications for U1271A
Accuracy ± (% of reading + counts of least significant digit)
Function Range Resolution 45 Hz to
65 Hz
30 Hz to
1 kHz
1 kHz to
5 kHz
5 kHz to
20 kHz
True RMS AC
Voltage1
300 mV 0.01 mV 0.7 + 20 1.0 + 25 2.0 + 25 2.0 + 40
3 V 0.0001 V 0.7 + 20 1.0 + 25 2.0 + 25 2.0 + 40
30 V 0.001 V 0.7 + 20 1.0 + 25 2.0 + 25 2.0 + 40
300 V 0.01 V 0.7 + 20 1.0 + 25 2.0 + 25 —
1000 V 0.1 V 0.7 + 20 1.0 + 25 — —
LPF (low pass filter)
enabled, applicable for
all voltage ranges and
resolution0.1 V
0.7 + 20
1.0 + 25@<200 Hz
5.0 + 25@<440 Hz
—
—
Accuracy ± (% of reading + counts of least
significant digit)
Function Range Resolution 45 Hz to 2 kHz Burden voltage/Shunt
True RMS AC
Current2
300 µA 0.01 µA 0.9 + 25 < 0.04 V/100 Ω
3000 µA 0.1 µA 0.9 + 25 < 0.4 V/100 Ω
30 mA 0.001 mA 0.9 + 25 < 0.08 V/1 Ω
300 mA 0.01 mA 0.9 + 25 < 1.00 V/1 Ω
3 A 0.0001 A 1.0 + 25 < 0.1 V/0.01 Ω
10 A 0.001 A 1.0 + 25 < 0.3 V/0.01 Ω
1. Notes for voltage specifications:
Overload protection: 1000 Vrms. For millivolt measurements, 1000 Vrms for short circuits with < 0.3 A
current.
Input impedance: 10 MΩ (nominal) in parallel with < 100 pF.
2. Notes for current specifications:
Overload protection for 300 μA to 300 mA range: 0.44 A/1000 V; 10 × 35 mm 30 kA fast-acting fuse.
Overload protection for 3 A to 10 A range: 11 A/1000 V; 10 × 38 mm 30 kA fast-acting fuse.
Specification for 300 mA range: 440 mA continuous.
Specification for 10 A range: 10 A continuous. Add 0.3% to the specified accuracy when measuring
signals > 10 to 20 A for 30 seconds maximum. After measuring currents > 10 A, cool down the
multimeter for twice the duration of the measured time before proceeding with low current
measurements.
Electrical Specifications (continued)
Find us at www.keysight.com Page 13
AC specifications for U1272A/U1273A and U1273AX
Accuracy ± (% of reading + counts of least significant digit)
Function Range Resolution 45 Hz to
65 Hz
20 Hz to
1 kHz
1 kHz to
5 kHz
5 kHz to
20 kHz
20 kHz to
100 kHz
True RMS AC
Voltage1
30 mV 0.001 mV 0.6 + 20 0.7 + 25 1.0 + 25 1.0 + 40 3.5 + 40
300 V 0.01 mV 0.6 + 20 0.7 + 25 1.0 + 25 1.0 + 40 3.5 + 40
3 V 0.0001 V 0.6 + 20 1.0 + 25 1.5 + 25 2.0 + 40 3.5 + 40
30 V 0.001 V 0.6 + 20 1.0 + 25 1.5 + 25 2.0 + 40 3.5 + 40
300 V 0.01 V 0.6 + 20 1.0 + 25 1.5 + 25 2.0 + 40 —
1000 V 0.1 V 0.6 + 20 1.0 + 25 1.5 + 25 — —
LPF (low pass filter)
enabled, applicable
for all voltage ranges
and resolution
0.6 + 20
1.0 + 25 @
< 200 Hz
5.0 + 25 @
< 440 Hz
—
—
—
ZLOW 1000 V 2.0 + 40 2 + 40 @ < 440 Hz
— — —
Accuracy ± (% of reading + counts of least
significant digit)
Function Range Resolution 45 Hz to 65 Hz 20 Hz to 2 kHz Burden voltage/Shunt
True RMS AC
Current2
300 µA 0.01 µA 0.6 + 25 0.9 + 25 < 0.04 V/100 Ω
3000 µA 0.1 µA 0.6 + 25 0.9 + 25 < 0.4 V/100 Ω
30 mA 0.001 mA 0.6 + 25 0.9 + 25 < 0.08 V/1 Ω
300 mA 0.01 mA 0.6 + 25 0.9 + 25 < 1.00 V/1 Ω
3 A 0.0001 A 0.8 + 25 1.0 + 25 < 0.1 V/0.01 Ω
10 A 0.001 A 0.8 + 25 1.0 + 25 < 0.3 V/0.01 Ω
1. Notes for voltage specifications:
Overload protection: 1000 Vrms. For millivolt measurements, 1000 Vrms for short circuits with < 0.3 A
current.
Input impedance: 10 MΩ (nominal) in parallel with < 100 pF.
ZLOW impedance: 2 kΩ (nominal).
The input signal is lower than the product of 20,000,000 V×Hz.
For 20 to 100 kHz accuracy: Three counts of the LSD per kHz of additional error is to be added for
frequencies > 20 kHz and signal inputs < 10% of range.
U1273AX only: For all AC voltage ranges, the accuracy is specified at 2.5% + 25 counts when
measuring below –20 °C for 20 to 45 Hz AC signals.
2. Notes for current specifications:
Overload protection for 300 μA to 300 mA range: 0.44 A/1000 V; 10 × 35 mm 30 kA fast-acting fuse.
Overload protection for 3 A to 10 A range: 11 A/1000 V; 10 × 38 mm 30 kA fast-acting fuse.
Specification for 300 mA range: 440 mA continuous.
Electrical Specifications (continued)
Find us at www.keysight.com Page 14
Specification for 10 A range: 10 A continuous. Add 0.3% to the specified accuracy when measuring
signals > 10 to 20 A for 30 seconds maximum. After measuring currents > 10 A, cool down the
multimeter for twice the duration of the measured time before proceeding with low current
measurements.
U1273AX only: The accuracy for the 300 μA range, 3000 μA range, and 30 mA is specified after the
Null function is used when measuring at temperatures below –20 °C. The Null function is used to
subtract the test lead resistance and thermal effect (by shorting the test leads).
U1273AX only: For all AC current ranges, the accuracy is specified at 2.5% + 25 counts when
measuring below –20 °C for 20 to 45 Hz AC signals.
Electrical Specifications (continued)
Find us at www.keysight.com Page 15
AC + DC specifications for U1272A/U1273A and U1273AX
Accuracy ± (% of reading + counts of least significant digit)
Function Range Resolution 45 Hz to
65 Hz
20 Hz to
1 kHz
1 kHz to
5 kHz
5 kHz to
20 kHz
20 kHz to
100 kHz
True RMS
AC + DC
Voltage1
30 mV 0.001 mV 0.7 + 40 0.8 + 45 1.1 + 45 1.1 + 60 3.6 + 60
300 mV 0.01 mV 0.7 + 25 0.8 + 30 1.1 + 30 1.1 + 45 3.6 + 45
3 V 0.0001 V 0.7 + 25 1.1 + 30 1.6 + 30 2.1 + 45 3.6 + 45
30 V 0.001 V 0.7 + 25 1.1 + 30 1.6 + 30 2.1 + 45 3.6 + 45
300 V 0.01 V 0.7 + 25 1.1 + 30 1.6 + 30 2.1 + 45 —
1000 V 0.1 V 0.7 + 25 1.1 + 30 1.6 + 30 — —
Accuracy ± (% of reading + counts of least significant digit)
Function Range Resolution 45 Hz to 65 Hz 20 Hz to 2 kHz Burden voltage/Shunt
True RMS
AC + DC
Current2
300 µA 0.01 µA 0.8 + 30 1.1 + 30 < 0.04 V/100 Ω
3000 µA 0.1 µA 0.8 + 30 1.1 + 30 < 0.4 V/100 Ω
30 mA 0.001 mA 0.8 + 30 1.1 + 30 < 0.08 V/1 Ω
300 mA 0.01 mA 0.8 + 30 1.1 + 30 < 1.00 V/1 Ω
3 A 0.0001 A 0.9 + 35 1.3 + 35 < 0.1 V/0.01 Ω
10 A 0.001 A 0.9 + 35 1.3 + 35 < 0.3 V/0.01 Ω
1. Notes for voltage specifications:
- Overload protection: 1000 Vrms. For millivolt measurements, 1000 Vrms for short circuits with < 0.3 A current.
- Input impedance: 10 MΩ (nominal) in parallel with < 100 pF.
- The input signal is lower than the product of 20,000,000 V×Hz.
- For 20 to 100 kHz accuracy: Three counts of the LSD per kHz of additional error is to be added for frequencies > 20 kHz and signal inputs < 10% of range.
- U1273AX only: For all AC voltage ranges, the accuracy is specified at 2.5% + 25 counts when measuring below –20 °C for 20 to 45 Hz AC signals.
2. Notes for current specifications:
- Overload protection for 300 μA to 300 mA range: 0.44 A/1000 V; 10 × 35 mm 30 kA fast-acting fuse.
- Overload protection for 3 A to 10 A range: 11 A/1000 V; 10 × 38 mm 30 kA fast-acting fuse.
- Specification for 300 mA range: 440 mA continuous.
- Specification for 10 A range: 10 A continuous. Add 0.3% to the specified accuracy when measuring signals > 10 to 20 A for 30 seconds maximum. After
measuring currents > 10 A, cool down the multimeter for twice the duration of the measured time before proceeding with low current measurements.
- U1273AX only: The accuracy for the 300 μA range, 3000 μA range, and 30 mA is specified after the Null function is used when measuring at temperatures
below –20 °C. The Null function is used to subtract the test lead resistance and thermal effect (by shorting the test leads).
- U1273AX only: For all AC current ranges, the accuracy is specified at 2.5% + 25 counts when measuring below –20 °C for 20 to 45 Hz AC signals.
Electrical Specifications (continued)
Find us at www.keysight.com Page 16
Temperature specifications1 - 4
Thermocouple
type
Range
Resolution
Accuracy ± (% of reading + as specified below)
U1271A U1272A U1273A/U1273AX
K
–200 to 1372 °C 0.1 °C 1% reading + 1 °C 1% reading + 1 °C 1% reading + 1 °C
–328 to 2502 °F 0.1 °F 1% reading + 1.8 °F 1% reading + 1.8 °F 1% reading + 1.8 °F
I
–210 to 1200 °C 0.1 °C — 1% reading + 1 °C 1% reading + 1 °C
–346 to 2192 °F 0.1 °F — 1% reading + 1.8 °F 1% reading + 1.8 °F
1. The specifications above is specified after 60 minutes of warm-up time.
2. The accuracy does not include the tolerance of the thermocouple probe.
3. Do not allow the temperature sensor to contact a surface that is energized above 30 Vrms or 60 V DC. Such voltages pose a shock hazard.
4. The temperature calculation is specified according to the safety standards of EN/IEC-60548-1 and NIST175.
Capacitance specifications5, 6
Range
Resolution
Accuracy ± (% of reading + counts of least significant digit)
U1271A U1272A U1273A/U1273AX
10 nF 0.001 nF 1 + 5 1 + 5 1 + 5
100 nF 0.01 nF 1 + 2 1 + 2 1 + 2
1000 nF 0.1 nF 1 + 2 1 + 2 1 + 2
10 μF 0.001 μF 1 + 2 1 + 2 1 + 2
100 μF 0.01 μF 1 + 2 1 + 2 1 + 2
1000 μF 0.1 μF 1 + 2 1 + 2 1 + 2
10 mF 0.001 mF 1 + 2 1 + 2 1 + 2
5. Overload protection: 1000 Vrms for short circuits with < 0.3 A current.
6. The accuracy for all ranges is specified based on a film capacitor or better, and after the Null function is used to subtract the test lead resistance and
thermal effect (by opening the test leads).
Electrical Specifications (continued)
Find us at www.keysight.com Page 17
Frequency specifications1, 2
Range
Resolution
Accuracy ± (% of reading +
counts of least significant digit)
Maximum input frequency
99.999 Hz 0.001 Hz 0.02 + 5
0.5 Hz
999.99 Hz 0.01 Hz 0.005 + 5
9.9999 Hz 0.1 Hz 0.005 + 5
99.999 kHz 1 Hz 0.005 + 5
999.99 kHz 0.01 Hz 0.005 + 5
> 1 MHz 0.1 Hz 0.005 + 5 @< 1 MHz
1. Overload protection: 1000 V; input signal is < 20,000,000 V × Hz (product of voltage and frequency).
2. The frequency measurement is susceptible to error when measuring low-voltage, low-frequency signals. Shielding inputs from external noise pickup is critical for
minimizing measurement errors. Turning on the low pass filter may help you to filter out the noise and achieve a stable reading.
Duty Cycle3
Mode Range Accuracy at full
scale
DC coupling 99.99% 0.3 % per kHz + 0.3 %
AC coupling 99.99% 0.3 % per kHz + 0.3 %
3. Notes for duty cycle specifications:
- The accuracy for duty cycle and pulse width measurements is based on a 3 V square wave input to the DC 3 V range. For AC couplings, the duty cycle range
can be measured within the range of 10% to 90% for signal frequencies > 20 Hz.
- The range of the duty cycle is determined by the frequency of the signal: {10 μs × frequency × 100%} to {[1 – (10 μs × frequency)] × 100%}.
- The pulse width (positive or negative) must be > 10 μs. The range of the pulse width is determined by the frequency of the signal.
Pulse Width4
Range Resolution Accuracy at full scale
999.99 ms 0.01 ms (duty cycle accuracy/frequency) + 0.01 ms
2000.0 ms 0.1 ms (duty cycle accuracy/frequency) + 0.1 ms
4. Notes for pulse width specifications:
- The accuracy for duty cycle and pulse width measurements is based on a 3 V square wave input to the DC 3 V range.
- The pulse width (positive or negative) must be > 10 μs. The range of the pulse width is determined by the frequency of the signal.
Electrical Specifications (continued)
Find us at www.keysight.com Page 18
U1271A and U1272A frequency sensitivity for voltage measurements 1, 2, 3
Minimum sensitivity (RMS sine wave) Trigger level for DC coupling
Input range 15 Hz to 0.5 Hz to 200 kHz Up to 1 MHz 0.5 Hz to 200 kHz
100 kHz U1271A U1272A
30 mV 3 mV 3 mV — — 5 mV
300 mV 6 mV 8 mV 40 mV 10 mV 15 mV
3 V 0.12 V 0.2 V 0.4 V 0.15 V 0.15 V
30 V 0.6 V 0.8 V 2.6 V 1.5 V 1.5 V
300 V 6 V 8 V @ < 100 kHz — 9 V @ < 100 kHz 9 V @ < 100 kHz
1000 V 50 V 50V @ < 100 kHz — 90 V @ < 100 kHz 90 V @ < 100 kHz
1. Maximum input for specified accuracy, refer to “AC specifications” on page 12.
2. 30 mV range applicable for U1272A only.
3. 200 kHz to 1 MHz range applicable for U1272A only.
U1273A/U1273AX sensitivity for voltage measurements4
Input range Frequency sensitivity and trigger level
Minimum sensitivity (RMS sine wave) Trigger level for DC coupling
Maximum input for specified
accuracy, refer to AC voltage
15 Hz to
100 kHz
0.5 Hz to
200 kHz
Up to
1 MHz
0.5 Hz to
200 kHz
30 mV 3 mV 3 mV — 5 mV
300 mV 7 mV 8 mV 38 mV 15 mV
3 V 0.12 V 0.2 V 0.48 V 0.15 V
30 V 0.8 V 0.8 V 3.5 V 1.5 V
300 V 6.7 V 8 V < 100 kHz — 11 V < 100 kHz
1000 V 67 V 67 V < 100 kHz — 110 V < 100 kHz
4. Maximum input for specified accuracy, refer to “AC specifications” on page 13.
Frequency sensitivity for current measurements5
Minimum sensitivity (RMS sine wave)
2 Hz to 30 kHz
Input range U1271A/U1272A U1273A/U1273AX
300 µA 100 µA 70 μA
3000 µA 70 µA 120 μA
30 mA 1.2 mA 1.2 mA
300 mA 12 mA 12 mA
3 A 0.12 A 0.12 A
10 A 1.2 A 1.2 A
5. Maximum input for specified accuracy, refer to “AC specifications” on page 12 and 13.
Electrical Specifications (continued)
Find us at www.keysight.com Page 19
Peak hold
Signal width Accuracy for DC Voltage and Current
Single event >1 ms Specified accuracy + 400
Repetitive >250 µs Specified accuracy + 1000
Decibel (dB) for U1272A and U1273A1, 2, 3
dB Reference Default reference
1 mW (dBm) 1 to 9999 Ω 50 Ω
1 V (dBV) 1 V 1 V
1. The reading of dBm is indicated in decibels of power above or below 1 mW, or decibels of voltage above or below 1 V. The formula is calculated according
to the voltage measurement and specified reference impedance. Its accuracy is depended on the accuracy of the voltage measurement. See Decibel (dBV)
accuracy table below.
2. Auto-ranging mode is used.
3. The bandwidth is according to voltage measurement.
Decibel (dBV) accuracy
dBV range Accuracy
Range Minimum Maximum 45 Hz to
65 Hz
20 Hz to
1 kHz
1 Hz to
5 kHz
5 kHz
20 kHz
20 kHz to
100 kHz
30 mV –56.48 –30.46 0.06 0.07 0.09 0.1 0.32
300 mV –36.48 –10.46 0.06 0.07 0.09 0.1 0.32
3 V –16.48 +9.54 0.06 0.09 0.14 0.19 0.32
30 V +3.52 +29.54 0.06 0.09 0.14 0.19 0.32
300 V +23.52 +49.54 0.06 0.09 0.14 0.19 —
1000 V +33.98 +60 0.06 0.09 0.14 — —
Measurement rate (approximate)
Function Times / second
U1271A U1272A/U1273A/U1273AX
ACV 7 7
DCV 7 7
Ω 14 14
Ω with offset compensation — 3
Diode 14 14
Auto diode — 3
Capacitance 4 (< 100 µF) 4 (< 100 µF)
DCA 7 7
ACA 7 7
Temperature 7 7
Frequency 2 (> 10 Hz) 2 (> 10 Hz)
Duty cycle 1 (> 10 Hz) 1 (> 10 Hz)
Pulse width 1 (> 10 Hz) 1 (> 10 Hz)
Find us at www.keysight.com Page 20
Ordering Information
Standard shipped accessories
Standard test leads, test probes with 4-mm tips,
K-type thermocouple and adapter, 4x AAA
alkaline batteries (4x AAA lithium batteries for
U1273AX only), Certificate of Calibration, UK 6
(test report), Quick Start Guide
Optional accessories
U1271A U1272A U1273A U1273AX
Measuring accessories (non-temperature)
U1161A
Extended test
lead kit
Includes two test leads (red and black), two test probes, medium-
sized alligator clips and 4-mm banana plugs.
– Test leads: CAT III 1000 V, CAT IV 600 V, 15 A
– Test probes (4-mm tips): CAT III 1000 V, CAT IV 600 V, 15 A
– Medium-sized alligator clips: CAT III 1000 V/CAT IV 600 V, 15 A
– 4-mm banana plugs: CAT II 600 V, 10 A
U1162A
Alligator clips
– One pair of insulated alligator clips (red and black).
Recommended for use with Keysight standard test leads.
– CAT III 1000 V, CAT IV 600 V, 15 A
U1163A
SMT grabbers
– One pair of SMT grabbers (red and black). Recommended for use
with Keysight standard test leads.
– Rated CAT II 300 V, 3 A
U1164A
Fine-tip test
probes
– One pair of fine-tip test probes (red and black). Recommended for
use with Keysight standard test leads.
– Rated CAT II 300 V, 3 A
U1168A
Standard test
lead kit
Includes two test leads (red and black), 4-mm test probes, alligator
clips, fine-tip test probes, SMT grabbers and mini grabber (black).
– Test leads: CAT III 1000 V, CAT IV 600 V, 15 A
– Test probe (19-mm tips): CAT II 1000 V, 15 A
– Test probe (4-mm tips): CAT III 1000 V, CAT IV 600 V, 15 A
(highly recommended for CAT IV environment)
– Alligator clips: CAT III 1000 V, CAT IV 600 V, 15 A
– Fine-tip test probes: CAT II 300 V, 3 A
– SMT grabber: CAT II 300 V, 3 A
– Mini grabber: CAT II 300 V, 3 A
U1583B
AC current
clamp
– Dual range: 40 A and 400 A
– Rated CAT III 600 V
– BNC-to-banana-plug adapter provided for use with DMMs
– -40 to 55 °C operating temperature
Find us at www.keysight.com Page 21
Ordering Information (continued)
Optional accessories (continued)
Measuring accessories (non-temperature)
U1180A
Thermocouple
adapter + lead
kit, J and K
types
Includes thermocouple adapter, thermocouple bead J-type and
thermocouple bead K-type.
– T/C adapter J/K-type
– T/C bead J-type: –20 to 200 °C
– T/C bead K-type: –20 to 200 °C
U1181A
Immersion
temperature
probe
– Type-K T/C for use in oil and other liquids
– Measurement range: –50 to 700 ºC
– Includes adapter U1184A for connection to DMM
U1182A
Industrial
surface
temperature
probe
– Type-K T/C for use on still surfaces
– Measurement range: –50 to 400 ºC
– Includes adapter U1184A for connection to DMM
U1183A
Air
temperature
probe
– Type-K T/C for use in air and non-caustic gas
– Measurement range: –50 to 800 ºC
– Includes adapter U1184A for connection to DMM
U1184A
Temperature
probe adapter
– Mini-connector-to-banana-plug adapter for use with DMM
U1185A
J-type
thermocouple
and adapter
– T/C adapter J/K-type
– T/C bead J-type: –20 to 200 °C
U1186A
K-type
thermocouple
and adapter
– T/C adapter J/K-type
– T/C bead J-type: –20 to 200 °C
Find us at www.keysight.com
This information is subject to change without notice. © Keysight Technologies, 2017, 2019, 2020, Published in USA, August 22, 2020, 5990-6425EN
Page 22
Learn more at: www.keysight.com
For more information on Keysight Technologies’ products, applications or services,
please contact your local Keysight office. The complete list is available at:
www.keysight.com/find/contactus
Ordering Information (continued)
Optional accessories (continued)
U1171A
Magnetic
hanging kit
For fastening the DMM to a steel surface so both hands are free
U1173A
IR-to-USB
cable
– For remote control and data logging to PC
– Maximum baud rate: 19,200 bits per second
U1174A
Soft carrying
case
The convenient way to carry your DMM and essential accessories
– Dimension: 9 inches (H) x 5 inches (W) x 3 inches (D)
U1177A
Bluetooth
Adapter
– Enables Bluetooth connection to Keysight handheld digital
multimeters
– Support the U1230, U1240, U1250 and U1270 Series handheld
multimeters
– Remote monitoring and data logging capabilities via Android
devices or Windows-based PC
– Recommended to use Lithium battery in lower than -20°C in
temperature for long hours of operation
Ohm and Power laws
Resistance Box
Wires
Power Source
Voltmeter and Ammeter
Revisions
2022 T. Vahabi, E. Horsley, A. Harlick
2017 C. Lee
2016 J. Ladan and R. M. Serbanescu
© 2016-2022 University of Toronto
This work is licensed under the Creative Commons Attribution-NonComercial-ShareAlike
4.0 Unported License (http://creativecommons.org/licenses/oby-nc-sa/4.0/)
1
http://creativecommons.org/licenses/oby-nc-sa/4.0/
Introduction to fitting methods
Background knowledge for Part I
• Python: arrays, numpy, pyplot, scipy, curve fit()
• Error Analysis Chi squared (�2), goodness of fit
• Physics: Ohm’s law. Review appropriate sections of your textbook.
Introduction
The function curve fit() is introduced for fitting linear data. You will perform voltage
and current measurements on a resistor to find the resistance via Ohm’s law.
You are expected to maintain a notebook (physical or electronic) where you record your
measurements, create plots, and write Python code appropriate for the lab.
This lab contains explicit questions for you to answer labelled with “Q”. They are
intended as prompts for analysis and discussion. The answers to the questions should be
organically interwoven into your report.
In this exercise, we will introduce how to fit experimental data to a certain function,
and get quantitative observations from the experiment.
The package “Notes on Error Analysis” can be found at https://www.physics.
utoronto.ca/~phy224_324/web-pages/Notes_Error.pdf. It introduces linear and non-
linear regression methods, aimed at finding the values of parameters which give the closest
agreement between the data and the theoretical model. You should read the section on
least-squares fitting.
Suppose our data consisted of N measurements (yi, xi) with i = 1, 2, ..., N . A first
step is to plot the data with error bars representing the reading error (or the
standard deviation �i) on each point. This gives a visual check for what relation our data has.
Next, assume that we want to make a function f that will predict a value ȳi if we call
the function with the measurement xi and some set of parameters p0, p1. . . that represents
the experiment (e.g. resistance, gravity, spring constant could all be parameters). Our
goal is to find the value of the parameters that will allow the function f to make the best
predictions given the available data.
We could use this function f to make predictions for each measurement pair (xi, yi),
and make guesses about the parameters until we find ‘good’ agreement, but a more robust
method is to use the data fitting capabilities of Python to find the parameter values for us,
using a form of linear regression.
2
https://www.physics.utoronto.ca/~phy224_324/web-pages/Notes_Error.pdf
https://www.physics.utoronto.ca/~phy224_324/web-pages/Notes_Error.pdf
Curve fitting
To make use of Python in our regression, we need to write our mathematical relationship
between x and y as a Python function. In this experiment we’ll be looking at an experiment
that we think is modeled by a linear equation y = ax+ b, where a and b are the parameters
we are trying to determine. In Python code this becomes
Note that the independent variable x must be the first argument. In order for
your model function to work it must be able to take a numpy array and return an array.
This function only makes a prediction of the measurement of y given x. The job of finding
the parameters is done by the scipy package in Python, using the curve fit() function from
the scipy.optimize module.
Every time you call curve fit() you will give it 3 arguments, and usually more. The first
argument is your model function that curve fit() will use to make predictions, followed
by the x data, and the y data. curve fit() can also take three additional arguments
— you can provide an initial guess for your parameters using the p0 keyword argument,
the uncertainties in the dependent data in the sigma keyword argument, and you should
(almost always) and force curve fit() to consider uncertainties as absolute values (instead
of relative values) using the absolute sigma=True keyword. Your code will then look like
this:
curve fit() returns two values. The first value p opt contains the estimates of the
parameters you used in the model (in this case p opt has two elements). The second value
p cov contains the covariance matrix giving the uncertainties in estimates of the parameters
you used in the model (in this case p cov is a 2 ⇥ 2 matrix). In most experiments the
important values in p cov will be the diagonal elements, which represent the variance (the
uncertainty–squared) of the parameters. An easy way to extract these values and convert
them to uncertainties is :
where sqrt and diag are functions from numpy that calculate the square root, and extract
the diagonal elements, respectively. p std will now contain your parameter uncertainties.
3
Curve fitting internals
Internally, curve fit() uses an algorithm to find the best parameters. It does this by
defining a metric called �2 that it tries to minimize. Starting with your initial guess for the
parameters, curve fit() will calculate the value of �2 based on the experimental data and
your model, and adjust the parameters systematically until it finds the minimum value of
�2 within a (very small) uncertainty.
For simple equations, like the linear model above, curve fit() will take approximately
seven tries to find the best set of parameters. With more complex non–linear functions it
can take about 50 tries if you make a good initial guess, and more than 1, 000 tries if you
make a bad initial guess. In the default setup curve fit() is configured to stop trying after
800 tries, where it will report that it failed and stop the program.
It is, however, possible for curve fit() to stop ‘successfully’ and have an ill fitting model
if your model function is inappropriate, your data is inconsistent, or your initial parameter
guesses were bad. In this case you might see that the parameters haven’t been changed from
your initial guess, or the variances are infinite (inf) or “not a number”(NaN).
We will use the metric �2 later to measure how good the model function fits the data,
but you don’t need to define it for curve fit() to work. In words, �2 can be written as
�2 =
X
measurements
✓
dependent data value - predicted value
dependent data measurement error
◆2
(1)
For a ‘good’ fit we want our model prediction to be about as close to each measurement
(the numerator) as the uncertainty in each measurement (the denominator). We square the
function because a model that is too high is just as bad as a model that it too low.
Mathematically, �2 is written as
�2 =
NX
i=1
✓
yi � y(xi)
u(xi)
◆2
(2)
where xi and yi are the data from the ith measurement, f(xi) is the prediction from the
model of the value yi, and u(xi) is the uncertainty of the ith measurement.
There are many keyword arguments to curve fit(), which can be found in the documen-
tation. Commonly, you may use maxfev to control the maximum number of function calls.
The default value is 800.
4
https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html
https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html
The experiment
We will be testing Ohm’s Law – the linear relation between voltage and current in elec-
trical circuits. The voltage is our independent variable, current is the dependent variable,
and resistance is the parameter we would like to measure. There are two subparts to the
experiment: testing a known resistor and testing a potentiometer.
Uncertainty from multimeters
Our later analysis requires an idea of the uncertainty in the measurements. Digital multi-
meters have two types of uncertainty:
• Error of accuracy which depends on function (DCV, ACV, DCA, ACA and Ohm
(⌦)). This error is provided by the instrument manufacturer. This error is expressed
as a percentage of the reading. Please check the link below for complete instrument
specifications. The reading can be done on di↵erent scales of the same function, which
changes the number of digits on display and also the error of accuracy.
• Error of precision which is due to fluctuations at the level of the last digit.
These errors are both present at the same time and vary depending on your reading, the
range of values it falls int, and the type of multimeter used. Use the instructions provided
in the multimeter manual to determine the values of uncertainties for your voltage, current,
and resistance (where appropriate).
Be sure to track the uncertainty in measurements from the multimeter. Also, keep in
mind that there are other sources of uncertainty that are harder to measure, like the quality
of electrical connections, change in the temperature of the resistor, etc.
Experimental Procedure
You will be provided with two multimeters, a board with electrical components (similar to
that shown in Figure 1, and enough wires to connect everything. Choose one resistor, and
one potentiometer for the experiment.
5
Figure 1: The board of electrical elements used in this experiment. The set of resistors is
on the bottom-right, the potentiometers are on bottom-left, lightbulb (needed for Part II of
this experiment) is in the top-right of the board.
For the known resistor, perform the following.
1. Connect the ammeter, voltmeter, and power supply to the chosen resistor as shown
schematically in Figure 2). Ask the TA if you’re in doubt. Note that Figures 3a and
3b show the visual representation for the set up and the closeup of the power supply
indicating appropriate terminals for the connection.
Figure 2: Circuit diagram of the experimental setup.
6
Ammeter
Voltmeter
Resistance Box
Power Supply
(a)
Power Supply
Wire Setup
(b)
Figure 3: Visual representation of the connections for step 1. Figure (a) shows the set up
for the resistor, the voltmeter and the ammeter. Figure (b) is a close up of the power supply
wire set up
2. Vary the voltage on the power supply.
3. Record the voltage and current from the multimeters, along with uncertainty. Make
sure to choose the most appropriate range on the multimeters that allows you to
measure your values with the highest precision.
4. Change the voltage, and record the new values – repeat su�cient number of times to
have enough data to confidently fit.
5. Save the data (on a memory stick or in a file you store online) as a text file (ex-
tension.txt) with the data in two columns: then first column being the independent
variable (voltage).
6. After performing all the above measurements, disconnect the power, and switch the
voltmeter to become a resistance meter. This will give you a reference value to compare
against.
7. Repeat these measurements for a potentiometer, making sure not to move the dial be-
tween measurements. If your resistor board has no potentiometer, use another resistor.
Resistors are marked with coloured bars to indicate their nominal resistance
through a code (there are many calculators for this online). As part of this
exercise, you may also compare your results against the nominal resistance ± the
tolerance.
7
iiiiii
o 060 0.340 0.047
0.080 0 U4 0.055
0.100 0.645 01064
0.120 0ㄒ99 0.072 01 01A
㐅
140kfno 160 1.104 0叫
80 ⼈255 a 98
0.200 1.408 0.107
Analyzing the data
We will analyze the dependency of the current on the voltage using a linear fitting program.
Ohm’s law for resistors sates
I =
V
R
. (3)
Thus, the resistance of a linear component can be determined by plotting I vs. V , and
measuring the slope.
There are other electrical components that have nonlinear voltage-current relations, like
diodes, transistors, and amplifiers. Using a linear model for these would result in a bad fit.
In Part II of this exercise, we will perform a nonlinear regression with a lightbulb.
Build a linear fitting program
Linear fitting is done via the Levenberg-Marquedt algorithm (an advanced least-squares
method), as implemented in the scipy.optimize module. Today, you will use the
curve fit() function (i.e. textttscipy.optimize.curve fit). Calculation of the statistics from
the output of textttcurve fit() will be done in the next exercise.
Here is the outline of the Python program for Part I:
• import the necessary modules and functions (e.g. numpy and curve fit())
• Read the data file into an array with the loadtxt() function.
• Extract the variables from the array columns.
• Define the model function f(x) = ax+ b.
• Call curve fit() with the function, data, and initial guess for the parameters.
• Output the calculated parameters.
• Create relevant plots (this includes plotting the residuals).
Write a program to perform a linear fit for the data you collected in this experiment. It
should create a plot of current vs. voltage with error bars and the line of best fit, and output
the calculated value of resistance (the slope of the line of best fit). Run this program using
the data for the resistor, and again using the data for the potentiometer.
Q1 In Ohm’s law, V = IR, the line should pass through I = V = 0. Did your linear
fit pass through zero as well? If it did not, why do you think that happened?
Q2 What result do you find for resistance if you force the line to pass through zero?
(i.e. try the model function f(x, a) = ax)
Q3 How does your resistance from using curve fit() compare to the value measured
with the multimeter?
8
Goodness of fit - reduced chi-squared
Recall that the �2 distribution gives a measure of how unlikely a measurement is. The more
a model deviates from the measurements, the higher the value of �2. But if �2 is too small,
it is also an indication of a problem: usually that there were not enough samples. This best
(most likely) value of �2 depends on the number of degrees of freedom of the data, v = N�n,
where N is the number of observations and n is the number of parameters. This dependence
is removed with the reduced chi-squared distribution,
�2red =
1
v
NX
i=1
✓
yi � y(xi)
u(yi)
◆2
(4)
where yi is the dependent data you measured, xi is the independent data, u(yi) is the
measurement error in the dependent data.
For �2red, the best value is 1:
�2red � 1 indicates that the model is a poor fit;
�2red > 1 indicates an incomplete fit or underestimated error variance;
�2red < 1 indicates an over-fit model (not enough data, or the model somehow is fitting
the noise).
Q4 Add a function to your program to calculate �2red. What values were computed?
How would you interpret your results?
Resistors for electrical circuits are designed to be very linear and reliable, so the
three measurements for resistance will likely be very close. The lines may even
be indistinguishable on the plot.
9
Nonlinear fitting methods
Nonlinear circuits
We continue with the curve fitting from the previous exercises, but extend it to power
law models. A lightbulb demonstrates various power laws; resistance and radioactive power
are both dependent on temperature for blackbodies. In this lab, we will examine these
relations with the voltage-current curve for a lightbulb.
Background knowledge for Part II
• Python: lists, arrays, numpy, scipy, pyplot, curve fit()
• Error Analysis Chi squared (�2), goodness of fit
• Physics: Power Law. You may need to review appropriate section of your textbooks
to analyze and interpret your data.
Introduction
An incandescent lightbult works by heating a tungsten filament until it glows. All matter
emits electromagnetic radiation, called thermal radiation, when it has a temperature above
absolute zero. The simple theoretical material, a blackbody, is one that absorbs all radiation
and follows a strict power law:
P = A�T 4, (5)
where � is the Stefan-Boltzmann constant (5.670373 ⇥10�8 W m�2K�4).
Real materials are not ideal blackbodies. The relation for these “grey bodies” adds an
emissivity, ✏ < 1,
P = A�✏T 4, (6)
The emissivity itself is typically not constant, and depends on temperature through a
power law. For tungsten this relation is
✏(T ) = 1.731⇥ 10�3T 0.663 (7)
Including the emissivity leads to a power law between power and temperature. There is
also a power law for the resistance of the bulb. In the simplest case, it is treated as linear
(R / T ), but for tungsten it is more accurately,
R(t) / T 1.209 (8)
Combining the dependencies on temperature with P = V I and V = IR, a power law
can be found between current and voltage. For an ideal black body with a linear relation
between resistance and temperature,
10
I / V 35 (9)
For most of this experiment, we are not concerned with the constant of proportionality.
However, when comparing the theoretical curve to your data you might need to define a
suitable value.
Analysis of power laws with logarithms
The tool for analyzing power laws is, again, logarithms. Start with the general power law,
y = axb, (10)
and take the logarithm of both sides,
log(y) = blog(x) + log(a). (11)
Thus, log(y) depends linearly on log(x), with slope b. We can view this linear relation
on a log-log plot (logarithmic scales for both x and y).
Linear regression works again, with the same linear model function, except using log(xi)
and log(yi) as the input data.
Note: The same downfalls of using transformations apply. Again, using curve fit(),
we can use a nonlinear function directly as our model function.
The experiment
We will observe the power law for blackbody radiation through a lightbulb’s voltage-current
graph. Set up the Ohm’s Law experiment as you did in Part I, but with a lightbulb instead
of a resistor, as shown in Figure 4.
Ammeter
Voltmeter
Power Supply
Lightbulb
Figure 4: Visual representation of the experimental set up used in this part of the experiment.
After setting up the apparatus do the following:
11
power
Xiii's
11
1. Adjust the power supply voltage to its lowest value.
2. Wait for the voltage and current to stabilize (it should not take long).
3. Record the voltage and current values.
4. Record the uncertainties in your measurements.
5. Repeat this process for at least 15 di↵erent values of voltage. Pay attention to the
frequency with which you collect the data - if the dependent values change quickly,
decrease the “step”.
6. Save the values in a text file (.txt) and save it on an external memory device or online.
The Python program
You will use your programs to compare the transformation method and the non-linear least-
squares method. The best parameters will be found with both methods, and used to plot
best fit curves over the data.
The program should be organized as follows:
• Import the required functions and modules (numpy, scipy.optimize.curve fit(),
matplotlib.pyplot).
• Define the model functions(linearized: f(x, a, b) = ax+ b,non–linear: g(x, a, b) = axb)
• Load the data and uncertainty measurements using loadtxt().
• Perform the linear regression on (log(xi),log(yi)) using f(x, a, b) as the model func-
tion.
• Perform the nonlinear regression on (xi,yi) using g(x, a, b) as the model function.
• Output both of the power law relations you calculated.
• Plot the error bars, both curves of best fit, and the theoretical curve. Include a legend
for the di↵erent curves.
• Plot all the same things on a log–log plot. One way of doing this is with the
pylab.loglog() function, another way is to call pylab.yscale(‘log’) and
pylab.xscale(‘log’) after you make the plot.
The a and b parameters in the two model functions represent di↵erent parameters in the
original, un-transformed, model function. Make sure you can convert between the functions
correctly to compare the parameters accurately.
Write the program, and run it using the data gathered in the experiment. Save all plots
and the parameters you determined.
Q5 Which regression method gave an exponent closer to the expected value? Can you
see the di↵erence on the plots?
12
Analyzing the quality of the fit
As covered in previous exercises, there are two ways that we can assess the quality of the fit
of our model: variance of the calculated parameters, and the reduced chi-squared statistic.
The variance of the parameters is returned by curve fit() as the diagonal
entries in the covariance matrix, p cov. Recall that the uncertainty in measurements
is understood as the standard deviation,
a = ā± �a, (12)
where �a =
p
V ar(a) In the python program, the variance of the first parameter in your
model function is given in curve fit()p cov[0, 0], the variance of the second parameter
in curve fit()p cov[1, 1], and so on.
Modify your program from the Python program section to calculate the stan-
dard deviation of the parameters.
Q6 What values did you find? Does the value of your fitted exponent fall within
the range of the blackbody values, 35 , with your calculated standard deviation? What
about in comparison to the expected value for tungsten?
Reduced chi-squared
Recall that the �2 distribution gives a measure of how unlikely a measurement is. The more
a model deviates from the measurements, the higher the value of �2. But if �2 is too small,
it’s also an indication of a problem: usually that there were not enough samples. Add a
function to your program to calculate �2red.
Q7 What values were computed? How would you interpret your results?
13
Your submission for this exercise should include:
• All sets of data, clearly labeled, presented in an appropriate manner (tables/figures).
• All uncertainties, uncertainty budgets, sample uncertainty calculations
• Important information about the set up (models of the multimeters, band colours of
the resistor used, any other details that might be relevant (variations, disturbances,
changes made (e.g. equipment swaps, heating noticed, lightbulb stops working, etc.)
• Answers to all the questions, weaved throughout the report.
• All relevant current vs voltage plots with su�cient captions
• All obtained values of the resistance with uncertainties
• All obtained values for power fit parameters with uncertainties
• Plots of residuals
• The final version of your Python code (included separately as a .py file)
• Analysis and Discussion of your results.
14
Ohmdata
V(V) I(A) Uncertainty (V)Uncertainty (I)
0.000 0.000 0.001 0.001
0.099 0.010 0.001 0.001
0.200 0.020 0.002 0.001
0.299 0.030 0.002 0.001
0.400 0.039 0.002 0.001
0.499 0.049 0.002 0.001
0.600 0.059 0.003 0.001
0.699 0.069 0.003 0.002
0.800 0.079 0.003 0.002
0.899 0.089 0.003 0.002
1.000 0.099 0.004 0.002
1
power_law_data 2.35.03 PM
Power voltage(V) Voltage(V) Current(A) uncertainty (V)uncertainty (I)
0.050 0.044 0.63 0.001 0.02
0.100 0.087 1.23 0.001 0.03
0.150 0.131 1.82 0.001 0.05
0.200 0.175 2.38 0.001 0.06
0.250 0.220 2.89 0.002 0.07
0.300 0.265 3.36 0.002 0.08
0.350 0.311 3.78 0.002 0.09
0.400 0.357 4.16 0.002 0.09
0.450 0.403 4.49 0.002 0.10
0.500 0.450 4.79 0.002 0.11
0.550 0.498 5.06 0.002 0.11
0.600 0.544 5.30 0.002 0.12
0.650 0.592 5.51 0.002 0.12
0.700 0.640 5.71 0.003 0.12
0.750 0.689 5.89 0.003 0.13
1
Explanations and Answers
0
No answers posted
Post your Answer - free or at a fee
NB: Post a homework question for free and get answers - free or paid homework help.
Get answers to: Ohm And Power Laws For Practical Physics or similar questions only at Tutlance.
Related Questions
- Looking For Help With Physics 1
- Looking For Help With Physics 1
- Deriving An Equation, Using An Integral From A Scientific Paper
- Conceptual Physics Lab Graph Homework
- Lab Report 3- Projectile Motion
- Lab 9B Feild Of A Earth Magnet
- Lab 9B Feild Of A Earth Magnet
- Lab 9B Feild Of A Earth Magnet
- Lab 9B Feild Of A Earth Magnet
- Lab 9B Feild Of A Earth Magnet
- Laboratory 7 - Cyclotron Orbits And The E/M Ratio Of The Electron
- 11Th Grade Advanced Physics Questions
- Fourth Year University Physics Report Writing
- Using Matlab To Solve Vibration Problem
- Heat Exchanger Design Assignment
- Consider A Simple Gas Turbine Power Plant. Air At Ambient Conditions Enters The Air Compressor At Point 1 And Exits After Compression At Point 2
- A Ramjet Has A Constant-Diameter Combustion Chamber Followed By A Nozzle Whose Throat Diameter Is 0.92
- Physics And Sustainability - Design Your Experiment
- A Project Assignment For Aerodynamics Course
- Kinematics Equation, Need To Answer This Question Using Full Solution
- Physics Week 5 Lab Buoyancy. Must Have Ket Labs
- Physics Lab Report For College Physics
- About Lab Report For Two Spherical Objects
- I Need A Physics Lab Report Asap
- Fluid Mechanics Bsc Online Exam Help With The Answer
- Fluid Mechanics Bsc Online Exam Help With The Answer
- Fluid Mechanics Bsc Online Exam Help With The Answer
- Fluid Mechanics Bsc Online Exam Help With The Answer
- Fluid Mechanic Bachelor Online Exam Help With The Answer
- Fluid Mechanic Bachelor Online Exam Help With The Answer
- Fluid Mechanic Bachelor Online Exam Help With The Answer
- Fluid Mechanics Bsc Online Exam Help With The Answer
- Thermodynamics Homework Help Please
- Physic Lab Report, Error And Uncertainty In Lab Measurements
- Engineering Exams, These Will Be In Two Weeks.
- Answer All Questions. Please Provide Clearly Commented Code. Symbolic Calculations Are Not Permitted
- Simple Pulley Systems - First Year University Physics
- Exploring Tension Undergraduate Physics Lab
- Lab Assignment (Magnetic Field)
- Physics Lab Assignment (Faraday’s Law)
- Python Function To Interpolate Data Tables
- Python Function To Interpolate Data Tables
- Electron Transport Mechanism In Semiconductor Materials
- Formal Lab Report On Latent And Specific Heat
- Fluid Dynamics Test Engineering
- Physics Exam Chapter 1-7 Openstax Physics Book
- Thermodynamics Help With Take Home Exam
- Physics Lab - Newton's 2Nd Law And Friction
- Consider A Moving Object And A Satellite; Their Relative Velocity Profile Is Given In Figure 1:
- Physics Homework Answers Needed