Keysight U1251 User manual

Keysight U1251B and U1252B
Handheld Digital Multimeter
Quick Start Guide

Keysight U1251B and
U1252B Handheld Digital
Multimeter
Quick Start Guide
The following items are included with your multimeter:
If anything is missing or damaged, please contact the nearest Keysight
Sales Office.
✔Silicone test leads ✔Rechargeable 8.4 V battery (for
U1252B only)
✔4 mm probes
✔Alligator clips ✔Power cord and AC adapter (for
U1252B only)
✔Printed Quick Start Guide
✔Certificate of Calibration
✔9 V alkaline battery (for U1251B
only)
NOTE
Your multimeter is capable of remote data logging. To use this feature,
you will need an IR-USB cable (U1173A, purchased separately) and the
Keysight GUI Data Logger Software (downloadable from
www.keysight.com/find/hhTechLib).
WARNING
Ensure the terminal connections are correct for that
particular measurement selection before starting any
measurement. To avoid damage to the device, do not
exceed the input limit.

U1251B and U1252B Quick Start Guide
Charging the Battery
NOTE
For the battery charger, the mains supply voltage should not
fluctuate by plus or minus 10%.
CAUTIONCAUTION
•Do not rotate the rotary switch from position when
charging the battery.
•Perform battery charging only with 7.2 V or 8.4 V NiMH
rechargeable battery, 9 V size.
•Disconnect test leads from all the terminals when charging
the battery.
•Ensure proper insertion of battery in the multimeter, and follow
the correct polarity.
Use the specified accessory, the 24 V DC
adaptor to charge the battery.
1Remove and disconnect the test leads from
the meter.
2Turn the rotary switch to the
position. Connect the power cord to the DC
adapter.
3Plug the Red (+)/ Black (–) banana
terminals of the DC adapter to the
and the COM terminals respectively. The
DC adaptor can be replaced with a DC
power supply in order to set the 24 V DC
output and the over current limitation to a
value more than 0.5 A. Ensure that the
polarity of the connection is correct.
4The primary display indicates “bAt” and
the ‘SbY” flashes on the secondary display
and a short tone sounds to remind you
whether to charge the battery or not. Press
to start charging the battery, or the
meter will automatically start the self-test
after the 24 V supply is applied. We
recommend not to charge the battery if its
capacity is over 90%.

U1251B and U1252B Quick Start Guide
Functions and Features
CAUTIONCAUTION
•Upon initial use (or after a prolonged storage period), the
rechargeable battery may require three to four charge/discharge
cycles before achieving maximum capacity. To discharge, simply
run the multimeter under the rechargeable battery's power until
it shuts down or the low battery warning appears.
•The multimeter may indicate that charging is complete after ten
minutes when charging a new rechargeable battery. This is a
normal phenomenon with rechargeable batteries. Remove the
rechargeable battery from the device, reinsert it, and repeat the
charging procedure.
Action Steps
Turns ON backlight Press .
Checks battery capacity Press and hold for >1 s.
Freezes the measured value Press .
Starts MIN/MAX/AVG recording Press and hold for >1 s.
Offsets the measured value Press .
Changes the measuring range Press .
Turns on auto range Press and hold for > 1 s.
Turns on dual display Press .
Starts manual data logging Press and hold for > 1 s.
Views the logged data Press for > 1 s, press
to scroll through the logged data.
Clears the logged data Press for > 1 s, press
for >1 s.

U1251B and U1252B Quick Start Guide
Input Terminals and Overload Protection
Measurement Functions Input Terminal Overload Protection
Voltage COM 1000 V R.M.S
Diode 1000 V R.M.S
< 0.3 A short circuit
current
Resistance
Capacitance
Temperature
Current (μA and mA) µA.mA COM 440 mA/1000 V 30
kA/fast-acting fuse
Current (A) A COM 11 A/1000 V 30
kA/fast-acting fuse

U1251B and U1252B Quick Start Guide
Performing Voltage Measurements
Measuring AC voltage
1Set the rotary switch to . For
and mode, press to ensure
is shown on the display.
2Connect the red and black test leads to
input terminals V. mV (red) and COM
(black) respectively.
3Probe the test points and read the display.
4Press to display dual
measurements. Parameter can be switched
consecutively.
Measuring DC voltage
1Set the rotary switch to or .
Ensure that is shown on the display.
2Connect the red and black test leads to
input terminals V. mV (red) and COM
(black) respectively.
3Probe the test points and read the display.
4Press to display dual
measurements. Parameters can be
switched consecutively.
NOTE
For measuring DC voltage from a
mixed signal in DC measurement
mode, ensure that the Filter is
enabled

U1251B and U1252B Quick Start Guide
Using the Filter
1To enter the Setup mode, switch off the
meter, then turn the rotary knob to any
non-OFF position while holding
until you hear a beep. You may release
once you hear the beep.
2Press or to scroll through the menu
items until FiLtE is shown in the secondary
display.
3Press or to enable the Filter.
4Press to save your changes.
5Press and hold until the meter
restarts and returns to its normal operating
mode.
CAUTIONCAUTION
To avoid possible electric shock or per-
sonal injury, enable the Filter to verify
the presence of hazardous DC voltages.
Displayed DC voltages can be influenced
by high frequency AC components and
must be filtered to assure an accurate
reading.

U1251B and U1252B Quick Start Guide
Performing Current Measurements
CAUTIONCAUTION
• If the current is ≤ 440 mA, connect the red and black test
leads to input terminals µA.mA (red) and COM (black).
• If the current is > 440 mA, connect the red and black test
leads to input terminals A (red) and COM (black).
Measuring AC current
1Set the rotary switch to or
. Press to ensure
is shown on the display.
2Connect the red and black test leads to
input terminals µA.mA (red) and COM
(black) or A (blue) and COM (black)
respectively.
3Probe the test points in series with the
circuit and read the display.
Measuring DC current
1Set the rotary switch to or
. Ensure that is shown on
the display.
2Connect the red and black test leads to
input terminals µA.mA (red) and COM
(black) or A (blue) and COM (black)
respectively.
3Probe the test points in series with the
circuit and read the display.
To perform current measurements, set up your multimeter as shown in the
figure below. For measuring DC current from a mixed signal in DC measure-
ment mode, ensure that the Filter is enabled.

U1251B and U1252B Quick Start Guide
Performing Resistance, Conductance, and
Continuity Measurements
1Set the rotary switch to .
2Connect the red and black test leads to input terminals
Ω(red) and COM (black) respectively.
3Probe the test points (by shunting the resistor) and read the display.
4Press to scroll through audible continuity, conductance, and
resistance tests as shown.
Audible
continuity

U1251B and U1252B Quick Start Guide
Performing Capacitance and Temperature
Measurements
Capacitance
1Set the rotary switch to .
2Connect the red and black test leads to
input terminals (red) and COM
(black) respectively.
3Connect the red test lead to the positive
terminal of the capacitor, and the black test
lead to the negative terminal.
4Read the display.
Temperature
1Set the rotary switch to . Press
to select temperature
measurement.
2Plug the thermocouple adapter (with the
thermocouple probe connected to it) into
input terminals (red) and COM (black).
3Touch the measurement surface with
the thermocouple probe.
4Read the display.

U1251B and U1252B Quick Start Guide
Frequency and Frequency Counter
Measurements
WARNING
• Use the frequency counter for low voltage applications.
Never use the frequency counter on AC power line
systems.
• For input more than 30 Vpp, you are required to use
frequency measurement mode available under the
current or voltage measurement instead of frequency
counter.
Frequency Measurement
During AC/DC voltage or AC/DC current
measurements, you can measure the signal
frequency by pressing at any time.
Frequency Counter Measurement
1Set the rotary switch to .
2Press to select the frequency
counter (Hz) function. “—1—” on the
secondary display means the input signal
frequency is divided by 1. This
accommodates for higher frequency range
of up to 985 kHz.
3Connect the red and black test leads to
input terminals V (red) and COM (black)
respectively.
4Probe the test points and read the display.
5If the reading is unstable or zero, press
to select division of input signal
frequency by 100. This accommodates a
higher frequency range of up to 20 MHz.
6The signal is out of range if the reading is
still unstable after step 5.

U1251B and U1252B Quick Start Guide
Square Wave Output (for U1252B only)
NOTE
Pressing is the same as pressing .
1Turn the rotary switch to . Default
display setting is 600 Hz on secondary display
and 50% duty cycle on primary display.
2Press or to scroll through the
available frequencies (there are 28
frequencies to choose from).
3Press to select duty cycle (ms) on
the primary display.
4Press or to adjust the duty cycle.
Duty cycle can be set for 256 steps and
each step is 0.390625%. The display only
indicates the best resolution with 0.001%.

Safety Notices Safety Information
This meter is safety-certified in compliance
with EN/IEC 61010-1:2001, UL 61010-1
Second Edition and CAN/CSA 22.2 61010-1
Second Edition, CAT III 1000 V/CAT IV 600 V
Overvoltage Protection, Pollution Degree II.
Use with standard or compatible test
probes.
Safety Symbols
CAUTIONCAUTION
A CAUTION notice denotes
a hazard. It calls attention
to an operating procedure,
practice, or the like that, if
not correctly performed or
adhered to, could result in
damage to the product or
loss of important data. Do
not proceed beyond a
CAUTION notice until the
indicated conditions are
fully understood and met.
WARNING
A WARNING notice
denotes a hazard. It calls
attention to an operating
procedure, practice, or the
like that, if not correctly
performed or adhered to,
could result in personal
injury or death. Do not
proceed beyond a
WARNING notice until the
indicated conditions are
fully understood and met.
Earth (ground) terminal
Equipment protected
throughout by double
insulation or reinforced
insulation
Caution, risk of electric
shock
Caution, risk of danger (refer
to the instrument manual for
specific Warning or Caution
information)
Category III 1000 V
overvoltage protection
Category IV 600 V
overvoltage protection
CAT III
1000 V
CAT IV
600 V
For further safety information details, refer to the
Keysight U1251B and U1252B Handheld Digital Multimeter User’s Guide.

This information is subject to change without notice.
© Keysight Technologies 2009 - 2014
Edition 6, August 2014
*U1251-90046*
U1251-90046
www.keysight.com