Stanley Fatmax FMHT77419, User Manual, Page: 26 / 174

26
Measuring Frequency and Duty Cycle
1. Connect the black test lead to the "COM" terminal and the red test
lead to the " " terminal.
2. Set the range switch to Hz/% position. Then press the "Hz/%"
button to select frequency measurement or duty cycle measurement,
the display will show the corresponding unit.
3. Connect the test leads across the source or load to be measured.
4. Read the output on the display.
Note:
1. For frequency measurements, the voltage of the input signal must
be between 1V rms and 20Vrms.
2. For duty cycle measurements, the voltage of the input signal must
be between 3Vp-p and 10Vp-p. If the frequency of input signal is too
low, the reading’s stability will decrease.
3. For both frequency and duty cycle measurements, if the voltage
exceeds the specified range, the error of reading may be out of the
specified accuracy range.
Automatic Power-off
The display will blink and the meter will go into Sleep mode if you
have not turned the rotary switch or pressed button for 15 minutes. To
arouse the meter from Sleep, just press a button.
To disable the automatic power-off feature, press and hold down
a button while rotating the rotaryswitch from "OFF" position to other
position.
MAINTENANCE
Warning
Except replacing battery and fuse, never attempt to repair or service
your meter unless you are qualified to do so and have the relevant
calibration, performance test, and service instructions.
General Maintenance
Periodically wipe the case with a damp cloth and mild detergent. Do
not use abrasives or solvents.
Dirt or moisture in the terminals can affect readings.
Clean the terminals as follows:
1. Set the range switch to OFF position and remove the test leads from
the meter.
2. Shake out any dirt which may exist in the terminals.
3. Soak a new swab with alcohol.
4. Work the swab around in each terminal.