Testing the EPC9 EPC9 Manual 21
Put the model circuit into the ”10 MOhm” setting, which simulates a 10 MΩ-pipette
that is open to the bath solution. Reset the amplifier (1), set E9SCREEN to VC
(”voltage clamp”) mode (2) and apply a test pulse of 5 mV amplitude (3) and 5 ms
duration (4). The current response will be displayed on the digital oscilloscope. If
your gain range is appropriate, i.e. 5 mV/pA (5) you should a see a rectangular
current of about 500 pA in response to the test pulse. This represents the ohmic
resistor you are recording from: I = U / R = 5 mV / 10 M = 500 pA. E9SCREEN
will online calculate the pipette resistance and update it in the Rmem field (6) where
you should read a value close to 10 MΩ.
A possible voltage offset can be automatically canceled by clicking on the Auto-V0
button (7). After doing so, the command potential will be set to 0 mV (8) and the V0
control (9) displays the offset potential. The baseline of the current response (10), the
voltage monitor V-mon (11) and the current monitor I-mon (12) should be close to
zero. You could also do the offset potential cancellation in a more classical way by
clicking into the V0 control (9) and dragging the mouse up and down until the first
segment in the oscilloscope and the I-mon display (12) match zero.
The steps listed above can be automatically executed by clicking on the SET-UP
button or pressing the ‘1’ key on the numerical keypad. This will execute the
Gentle CC-Switch: ON
Relative Value
Last V-memb
CC Fast Speed
Sound
Volume
Hz/MΩ Rmem
Sound
100 %
100
Scope
1. Amplifier
CC-range: 1pA/mV
Test Pulse
Amplitude
5.0 mV
Duration
5.0 ms
Imon2
Gain
1.02 x
Clear
Reset
OverlayClose
Stimulus External
Off20 µs
Noise 0.00 A
Leak Subtraction
Off TrackAuto
RsComp
OffOff
CSlow
<>
1.00 pF
RSeries 5.0 MΩ
Range Off Cap Track
Auto
CFast
<>
0.00 pF
50 %
0.5 µs
Auto
Filter 2 2.9 kHzBessel
Filter 1
Bessel 10 kHz
Rmem 10.0 MΩ
V-mon 0.0 mV
I-mon 3.53 pA
Mode VC
Vo -2.8 mV
TrackAuto
LJ 0.0 mV
Gain
5.0 mV/pA
ClipV-memb
0.0 mV
+/-
emptyemptyemptyempty
WHOLE-CELLON-CELLSET-UP
Record
Delay Off
Help
500. pA
1.20 ms
2
3
4
5
6
7
8
9
10
11
12
1
EPC9 Patch-Clamp Amplifier, v8.3
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