5 rise time – Multichannel Systems STG1000 Manual User Manual

Page 64

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Stimulus Generator 1000 Series User Manual

58

11.5 Rise Time

The rise time of the voltage output is constant and independant from the stimulus protocol.
The rise time of the current output is no fixed hardware property.The kinetics depend on the
amplitude of the current pulse and the load resistance, that is, generally the electrode
impedance. The resistance affects the kinetics much stronger than the amplitude.

Generally, this does not make much difference for biological applications. If you have very time-
critical applications
, or if you use very short pulses, you should check the output of the STG
with an oscilloscope before starting the experiment.

Amplitude dependency of rise time

The higher the current amplitude, the higher the rise time. The rise time (1090%) was
measured with increasing current amplitudes and a constant load resistance of 10 kilohms. The
output current slope can be estimated at 100 μA/μs, but the relationship is not linear as shown
by the following (Boltzmann fitted) curve.

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