Molecular Devices Axoclamp 900A, Руководство пользователя

Страница: 64 / 213

User Guide for Axoclamp 900A
5. The ‘V’ meter in the software will drop to about 47 mV.
6. Check
DC Restore
.
7. The ‘V’ meter will return to 50 mV. This demonstrates the DC gain is
very high (typically > 1,000,000).
8. Reduce the Voltage Clamp Control (AC) Gain to 500 and note the ‘V’
meter stays at 50 mV indicating that the high DC gain is still clamping
the voltage even at low AC gain.
9. Verify that the AC gain is low. Uncheck
DC Restore
and note that the
‘V’ meter reading drops to less than 40 mV, showing a > 10 mV loss of
DC voltage clamp.
Tutorial 5: Auto Mode Switching
In addition to manually controlled mode switching from Axoclamp 900A
Commander, Axoclamp 900A has the ability to automatically switch
between I
‐
Clamp and V
‐
Clamp modes and back again. Auto mode
switching allows the user to set up parameters to switch automatically
from I
‐
Clamp mode to either dSEVC mode or TEVC mode and back to
I
‐
Clamp mode. The switching can be triggered by an external input or by a
positive or negative V
m
threshold crossing.
Prior to enabling Auto Mode Switching:
I
‐
Clamp mode must be configured.
The voltage
‐
clamp mode that will be switched into must also be
configured (by following the procedures outlined in the appropriate
tutorial).
The switch to V
‐
Clamp mode can be initiated by:
The external MODE BNC input going high (2–5 V) or low (0–0.8 V).
50