Fluke 187 사용자 설명서
Making Measurements
Measuring Pulse Width
3
3-25
To measure duty cycle, set up the meter to measure
frequency; then press
frequency; then press
N
a second time. You can
select the level the meter uses by pressing
[
to
trigger on the positive slope or
]
to trigger on the
negative slope. A typical duty cycle display is shown in
Figure 3-16.
Figure 3-16.
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Figure 3-16. Duty Cycle Display
For 5 V logic signals, use the 5 V dc range. For 12 V
switching signals in automobiles, use the 50 V dc range.
For sine waves, use the lowest ac or dc range that does
not result in multiple triggering. A manually-selected lower
switching signals in automobiles, use the 50 V dc range.
For sine waves, use the lowest ac or dc range that does
not result in multiple triggering. A manually-selected lower
input range will often measure better than the AUTO-
selected input range.
selected input range.
If a duty cycle reading is unstable, press
M
until the
AVG annunciator comes on and the average reading
appears in the secondary display.
appears in the secondary display.
Measuring Pulse Width
The pulse width function allows you to measure the
amount of time a signal is high or low within a given
period. See Figure 3-17. The measured waveform must
be periodic
amount of time a signal is high or low within a given
period. See Figure 3-17. The measured waveform must
be periodic
;
its pattern must repeat at equal time intervals.