Tutorials
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21
Chapter 3
Figure 2.13
The transients result from the charging of the 5 pF capacitance of the model cell,
which simulates the capacitance of a patch electrode. In a real experiment these
transients are undesirable because they may saturate the amplifier, leading to
distortions in the measured currents. They can be eliminated by using the Cp Fast
and Cp Slow controls in the main window of the MultiClamp Commander.
8. Place the mouse cursor over the button (dual control) opposite Cp Fast. The cursor
changes to crossed arrows. (See the figure below.) While holding down the Shift
key (to magnify the movement; see Chapter 2) use the glider, sliding the mouse
horizontally and vertically, to change the values of the time constant and
capacitance, respectively. Alternatively, you can place the mouse cursor over each
parameter display in turn, and use the glider to adjust each individually.
Figure 2.14
Notice that you can change the amplitude and, to a lesser extent, the decay time
constant of the transients on the oscilloscope. With Cp Fast capacitance set to
about 5 pF the transients should be minimized.
9. An alternative way to cancel the transients is by pressing the Auto button opposite
Cp Fast. The algorithm should find optimum values of about 5 pF and 1
µ
s. In
