Technical data

30 Agilent U1251B/U1252B User’s and Service Guide
2 Making Measurements
Frequency Counter
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 a
higher frequency range of up to 985 kHz.
3 Connect the red and black test leads to the input
terminals V and COM respectively.
4 Probe the test points and read the display.
5 If the reading is unstable or is zero, press to select
the division of the input signal frequency by 100. This
accommodates for 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.
While the secondary display shows “- 1- “, you may scroll
through the pulse width (ms), duty cycle (%) and frequency
(Hz) measurements by pressing .
WARNING
• Use the frequency counter for low voltage applications only.
Never use the frequency counter for line power system.
• 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.