Iso-Tech IDM 103N Instruction Manual page 19

Making Basic Measurements
Measuring Hz / RPM
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Note – Connect the red test lead to the "
VΩHz " terminal
and the other (black) test lead to the "COM" terminal.
Set the rotary function selector to "Hz RPM" position to meas-
ure the frequency or RPM with the blue switch.
Connect the test leads to the circuit to be measured.
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