Multichannel Systems STG1000 Manual - Manual (Page 65)

Analog Output Signals
59
Resistance dependency oft rise time
The higher the load resistance, the higher the rise time. The rise time (1090%) was measured
with increasing load resistances and a constant current amplitude of 100 μA. For 100 μA pulses,
the relationship is linear up to the maximum load resistance (please see "Current Mode") as
shown by the following (Boltzmann fitted) curve.
Stimulus output comparison
The following figures are examples for demonstrating how the amplitude and resistance will
affect the kinetics of a current pulse. These images document also that in contrast to the
current mode, in voltage mode, the rise time is constant and not dependant on the amplitude
or load resistance.
The graphs were generated by a standard oscilloscope. The devices were set up according to the
recommendations under "Voltage Mode" and "Current Mode". The same pulse protocol and the
same channel number of the STG outputs was used for measuring the voltage and the current
output. The yellow traces show the voltage (U) output; cyan traces are from the current output
(+I) with a load resistance of 10 k
Ω, and green traces show the TTL output from the Sync Out
that was used for triggering the oscilloscope
.