TEC-B-01 User Manual
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version 1.1
page 13
4.3.
Connections and Operation
Checking the Configuration with the Cell Model
Make the basic settings (see chapter 4.2).
Connect the P
EL
BNC jack of the cell model to the BNC connector at the potential headstage.
Connect the BNC jack C
EL
to the connector at the current headstage.
Switch the CELL membrane switch (see Figure 4) to the desired position.
Set the GND switch (see Figure 4) to ON.
Turn POWER switch of the amplifier on.
Now you can adjust the amplifier and apply test pulses to the cell model. Connection to both BNC
connectors gives access to the cell via a potential and current electrode with 1 M
resistance. In the
upper position, the R
M
switch simulates a cell membrane with a resistance of 10 k
. In the lower
position, a cell membrane with 100 k
is simulated. The membrane capacity is always 100 nF (see
also chapter 5.5).
5. Test and Tuning Procedures
Important
: The TEC-B-01 and BA amplifiers should be used only in warmed-up condition, i.e. 20 to
30 minutes after turning power on.
The following test and tuning procedures are necessary for optimal recordings. It is recommended first
to connect a cell model to the amplifier to perform some basic adjustments and to get familiar with
these procedures.
5.1. Current
Headstage
Bias Current Adjustment
Caution:
It is important that this tuning procedure is performed ONLY after a warm-up period of at
least 30 minutes!
The tuning procedure must be performed regularly (at least once a month) with great care since the
bias current changes over time and it determines the accuracy of the TEC system.
The TEC-03X is equipped with a high-voltage current source that is connected to the current injecting
electrode and performs the current injection. This current source has a high-impedance floating output.
Therefore, the zero point (the zero of the bias current) of the current source must be defined, i.e.
without an input signal there should not be an output current.
Since the high-voltage FET amplifiers that are used become warm from the internal heat dissipation
and their characteristics are strongly temperature dependent, the calibration procedure has to be done
periodically by the user.
The tuning procedure is done using the C. HEADSTAGE BIAS CURRENT control and one resistance
of a few k
and one of a few M
or a cell model. It is based on Ohm's Law
(U = R * I).
