User's Manual

32 Agilent U1251A/U1252A User’s and Service Guide
2 Making Measurements
Frequency Counter
Set up the multimeter to measure frequency as shown in
Figure 2- 6. Probe the test points and read the display.
WARNING
• Use the frequency counter for low voltage applications only. Never use
the frequency counter for line power system.
• For inputs more than 30 Vpp, you are required to use frequency
measurement mode available under the current or voltage
measurement instead of frequency counter.
NOTE
• Press to select the Frequency counter (Hz) function. “-1-“ on
the secondary display means the input signal frequency is divided by 1.
This allows signals of up to a maximum frequency of 985 kHz to be
measured.
• If the reading is unstable or is zero, press to select the division
of the input signal frequency by 100. This allows for a higher frequency
range of up to 20 MHz to be measured.
• The signal is out of range if the reading is still unstable after the above
step.
• While the secondary display shows “-1-“, you may scroll through the
pulse width (ms), duty cycle (%), and frequency (Hz) measurements by
pressing .