4 - 38HOW TO USE THE INSTRUMENT

TRIGGER

LINE

-Connect a sine-wave signal of 4 V/300 Hz to channel 1.

-Simultaneously press the STATUS and TEXT OFF keys.

-Press AUTOSET.

-Select a timebase speed of 1 ms/div.

-Press the TRIGGER key.

-Press the softkey next to the function ’ch1 line’ to select ’line’.

When ’line’ is selected, this function is intensified. The line frequency is used as the trigger source.

-Slowly vary the frequency of the sine-wave input signal.

Observe that when the input frequency is close to an integer multiple of the line frequency, the running sine wave slows down or even stands still. Line triggering can be used to display signals or signal components that are related to the line frequency (e.g., hum or power supply ripple).

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Fluke PM3370B Trigger Line, 38HOW to USE the Instrument, Slowly vary the frequency of the sine-wave input signal