Keysight U1251, U1252 Quick Start Manual

Keysight U1251B and U1252B
Handheld Digital Multimeter

Quick Start Guide

Keysight U1251B and

NOTE

WARNING

U1252B Handheld Digital
Multimeter

Quick Start Guide

The following items are included with your multimeter:

✔ Silicone test leads
✔ 4 mm probes
✔ Alligator clips
✔ Printed Quick Start Guide

✔ Rechargeable 8.4 V battery (for

U1252B only)

✔ Power cord and AC adapter (for

U1252B only)

✔ Certificate of Calibration
✔ 9 V alkaline battery (for U1251B

only)

If anything is missing or damaged, please contact the nearest Keysight
Sales Office.

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).

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.

Charging the Battery

NOTE

CAUTIONCAUTION

Use the specified accessory, the 24 V DC
adaptor to charge the battery.

1 Remove and disconnect the test leads from

the meter.

2 Turn the rotary switch to the

position. Connect the power cord to the DC
adapter.

3 Plug 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.

4 The 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%.

For the battery charger, the mains supply voltage should not
fluctuate by plus or minus 10%.

• 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.

U1251B and U1252B Quick Start Guide

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.

Functions and Features

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

Resistance

Capacitance

Temperature

Current (μA and mA) µA.mA COM 440 mA/1000 V 30

Current (A) A COM 11 A/1000 V 30

< 0.3 A short circuit
current

kA/fast-acting fuse

kA/fast-acting fuse

U1251B and U1252B Quick Start Guide

Performing Voltage Measurements

Measuring AC voltage

1 Set the rotary switch to . For

and mode, press to ensure

is shown on the display.

2 Connect the red and black test leads to

input terminals V. mV (red) and COM

(black) respectively.

3 Probe the test points and read the display.

4 Press to display dual

measurements. Parameter can be switched
consecutively.

Measuring DC voltage

1 Set the rotary switch to or .

Ensure that is shown on the display.

2 Connect the red and black test leads to

input terminals V. mV (red) and COM

(black) respectively.

3 Probe the test points and read the display.

4 Press 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

1 To 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.

2 Press or to scroll through the menu

items until FiLtE is shown in the secondary
display.

3 Press or to enable the Filter.

4 Press to save your changes.

5 Press and hold until the meter

restarts and returns to its normal operating
mode.

CAUTIONCAUTION

To avoid possible electric shock or per­sonal 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

Measuring AC current

1 Set the rotary switch to or

. Press to ensure

is shown on the display.

2 Connect the red and black test leads to

input terminals µA.mA (red) and COM
(black) or A (blue) and COM (black)
respectively.

3 Probe the test points in series with the

circuit and read the display.

Measuring DC current

1 Set the rotary switch to or

. Ensure that is shown on

the display.

2 Connect the red and black test leads to

input terminals µA.mA (red) and COM
(black) or A (blue) and COM (black)
respectively.

3 Probe the test points in series with the

circuit and read the display.

• 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).

U1251B and U1252B Quick Start Guide

Performing Resistance, Conductance, and

1 Set the rotary switch to .

2 Connect the red and black test leads to input terminals

Ω (red) and COM (black) respectively.

3 Probe the test points (by shunting the resistor) and read the display.

4 Press to scroll through audible continuity, conductance, and

resistance tests as shown.

Audible
continuity

Continuity Measurements

U1251B and U1252B Quick Start Guide

Performing Capacitance and Temperature

Capacitance

1 Set the rotary switch to .

2 Connect the red and black test leads to

input terminals (red) and COM
(black) respectively.

3 Connect the red test lead to the positive

terminal of the capacitor, and the black test
lead to the negative terminal.

4 Read the display.

Temperature

1 Set the rotary switch to . Press

to select temperature

measurement.

2 Plug the thermocouple adapter (with the

thermocouple probe connected to it) into
input terminals (red) and COM (black).

3 Touch the measurement surface with

the thermocouple probe.

4 Read the display.

Measurements

U1251B and U1252B Quick Start Guide

Frequency and Frequency Counter

WARNING

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

1 Set the rotary switch to .

2 Press 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.

3 Connect the red and black test leads to

input terminals V (red) and COM (black)
respectively.

4 Probe the test points and read the display.

5 If 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.

6 The signal is out of range if the reading is

still unstable after step 5.

Measurements

• 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.

U1251B and U1252B Quick Start Guide

Square Wave Output (for U1252B only)

NOTE

1 Turn the rotary switch to . Default

display setting is 600 Hz on secondary display
and 50% duty cycle on primary display.

2 Press or to scroll through the

available frequencies (there are 28
frequencies to choose from).

3 Press to select duty cycle (ms) on

the primary display.

4 Press 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%.

Pressing is the same as pressing .

U1251B and U1252B Quick Start Guide

Safety Notices Safety Information

CAUTIONCAUTION

WARNING

CAT III
1000 V

CAT IV

600 V

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.

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.

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

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

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