26 • Tutorials
MultiClamp 700A Theory and Operation, Copyright 2000, 2001 Axon Instruments, Inc.
The relatively slow rise in the Scaled Output current trace (~1 ms) is a
manifestation of series resistance error. The goal is to speed up this risetime using
Rs compensation.
8. Check the Rs Compensation checkbox, set Bandwidth to 5 kHz, and ensure that
the Prediction and Correction controls change together.
Figure 2.20
Using glider control, slowly advance the percent setting under Prediction or
Correction while watching the Scaled Output trace on the oscilloscope. The trace
becomes noisier, the rising edge is speeded up, and a transient develops at the
rising edge. As the settings are increased beyond about 80% the transients become
larger, and then rapidly escalate into a full-blown oscillation. The art of Rs
compensation is to choose a combination of Bandwidth, Prediction and Correction
that provides maximal compensation without oscillation. Full details are given in
SERIES RESISTANCE COMPENSATION in Chapter 5.
9. The MultiClamp 700A is designed to be used with an external pulse generator or
computer to provide voltage-clamp (and current-clamp) command steps. However,
the Pulse button in the MultiClamp Commander allows you to apply simple, on-off
steps with a selectable amplitude and duration.
Figure 2.21
Experiment with different pulse settings, monitoring the Scaled Output trace while
repeatedly pressing the Pulse button. Note that only a discrete list of pulse
durations is allowed (seen by positioning the mouse over the duration field and
clicking the right button).
To Next Page
Loading...
Need help?
General
