Figure 5-28.Open and short circuit display.
The pulse generator provides dynamic testing for certain types of devices by driving the control input
of the device under test. The normal two-terminal mode of testing can be considered a static test, since
devices with three or more terminals are not tested in their active mode. However, with the pulse
generator, an in-circuit active test is possible.
In the PULSE mode, this circuit uses the zero crossing of the test signal to trigger the start of the
pulse. When positive (+) is enabled, a positive-going zero crossing triggers a positive pulse. When
negative (-) is enabled, a negative-going zero crossing triggers a negative pulse. If both are enabled, then
both positive and negative pulses are produced on alternate crossings (composite pulses). Once a pulse is
triggered, its duration is set by the WIDTH control knob. Figure 5-29 shows the waveforms for three
pulse polarity types at various settings of the WIDTH control.
Figure 5-29.Pulse generator waveforms.
The LEVEL control adjusts the peak of each pulse from zero to 5 volts with the polarity dependent
on the pulse polarity selected. When an open circuit is present, a maximum output of 5 volts peak-to-peak