TEC-B-01 User Manual
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version 1.1
page 8
Set the MODE OF OPERATION switch to OFF.
Important
: The tuning procedure
must not
be done in VC mode!!
Connect the electrode connector of the TEC-B-01 headstage to ground. If parasitic oscillations
occur use a 10 k
resistor for grounding.
Switch the digital display (#
9
) to V
CEL
(potential output of the current electrode) using switch #
10
.
Set the reading of the display to 0 using the OFFSET potentiometer (#
11
).
After tuning the current electrode potential OFFSET simulate an electrode by replacing the 10 k
resistor with a much larger resistor (e.g. 1 M
).
The digital display (and the CURRENT ELECTRODE potential connector (CEL x10mV) (#
18
))
now shows a voltage deflection that is related to the BIAS current of the headstage according to
Ohm's Law. Cancel this voltage by tuning the BIAS C
EL
trim pot (#
12
). The current is 0 if the
voltage deflection is 0.
Note
: Due to the characteristics of the high voltage OpAmps the V
CEL
display may fluctuate around the
baseline of 0 mV by some mV. With a 1 M
resistor (as used in the cell model) 1 mV corresponds to
1 nA. Keeping in mind that the display accuracy of the current is 10 nA in the last digit this is
insignificant.
Important
: The bridge amplifier it has a BIAS current as well and must be adjusted as described in the
bridge amplifier user manual.
(13)
CAP.COMP. potentiometer
Control for the capacity compensation of the CURRENT electrode or the signal connected to the EXT
IN connector #
16
(potentiometer with OFF position, clockwise).
Note
: For experiments with oocytes, it is recommended to switch the CAP.COMP potentiometer to
OFF position.
Important
: If the CAP. COMP is switched off, the BUZZ function for the C
EL
is also disabled.
(14)
Current HEADSTAGE
connector
Connector for the current headstage.
(15)
COMMAND IN ÷10 mV
connector
BNC connector for an external COMMAND voltage in VC mode (sensitivity: ÷10 mV). The signal
form remains unchanged.
(16)
EXT IN 1 µA/V
connector
BNC connector for connecting an external voltage signal. This can be used to operate the TEC-B-01
module as a constant current source, e.g. for iontophoresis. Scaling is 1 µA / V, i.e. 100 mV connected
at EXT IN leads to a current of 100 nA at the current electrode.
(17)
CURRENT OUT
connector
BNC connector providing the current signal. The scaling is set by switch #
5
. The filter is set by switch
#
4
.
