Multichannel Systems STG4002 Manual - Manual (Page 92)

Stimulus Generator 4002 Manual
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Example 3: Influence of the length of a current pulse and a high load resistance. Current pulse
with programmed 16 μA for 100 μs and 20 μs interval and 1 M
 load resistance. The load
resistance is very high. Please keep in mind that the load resistance of 1 M
is parallel toM
of the probe of the oscilloscope. That means, the load resistance is reduced to 900 k
only
The pulse is biphasic, and 16 μA which is a hundredth of the limit of the maximum capacity of the
STG 4002. Green trace = current output (+I), pink trace = TTL trigger output from the Sync Out.
Result of Example 3: The current output signal is delivered strongly modified because of the
high load resistance of 1 M
, and the duration of the pulse, 100 μs and the interval. Before the
pulse is reaching its maximum, it has to turn into its invert phase. Before the pulse is reaching its
minimum, it is cut off. Please see example 4: If the duration of pulse and interval is much longer,
1 ms, the pulse shape of the delivered signal is much better.