HEKA EPC 9 - Step 5: Measuring the Noise of the Amplifier

Testing the EPC9 EPC9 Manual 29
Step 5: Measuring the Noise of the Amplifier
Now let us come to the final section of the tutorial and check the intrinsic noise of the
amplifier. E9SCREEN has a built in feature that allows you to easily and quickly
check the noise of your amplifier and to minimize your setup’s noise, e.g., by
optimizing the grounding of the setup.
First, remove anything from the probe and shield its input with the metallic cap.
Now click the Noise button (1) to start the noise test. In the noise-test
mode no stimulation will occur. Instead, E9SCREEN will calculate the
noise of the current monitor 2 (Imon2) and display it in (2). Select the
highest feedback resistor of the preamplifier, which has the lowest
intrinsic noise by switching into a gain of 50 mV/pA or higher (3).
Note: The three different gain ranges of the EPC9 are separated by lines in the
gain popup menu. The low-gain range goes from 0.005 to 0.2, the
medium-gain range from 0.5 to 20 and the high-gain range from 50 to
2000 mV/pA.
Note: Because of poor dielectric properties in the internal switch, the model
circuit introduces excess random noise above the level that can be
obtained with a gigaseal.
EPC9 Patch-Clamp Amplifier, v8.3
Sound
Scope
1. Amplifier
Test Pulse
Amplitude
5.0 mV
Duration
100.0 ms
Imon2
Gain
100.00 x
Clear
Reset
OverlayClose
Stimulus External
Off20 µs
Noise 83.9 fA
Leak Subtraction
Off TrackAuto
RsComp
OffOff
CSlow
<>
1.00 pF
RSeries 5.0 MΩ
Range Off Cap Track
Auto
CFast
<>
0.00 pF
100 %
8.0 µs
Auto
Filter 2 2.9 kHzBessel
Filter 1
Bessel 10 kHz
Rmem 41.4 MΩ
V-mon 0.0 mV
I-mon -37.8 fA
Mode VC
Vo -2.7 mV TrackAutoLJ 0.0 mV
Gain
50 mV/pA
ClipV-memb
0.0 mV
+/-
emptyemptyemptyempty
WHOLE-CELLON-CELLSET-UP
Record
Delay Off
Help
84.7 fA
512. fA
25.0 ms
3
4
5
6
1
2