NPI SEC-05LX, Operating Instructions Manual

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SEC SYSTEMS WITH LINEAR (x1 AND x10) MODE
General Description
The linear mode of the SEC amplifier is an “unswitched” operation mode of the SEC, working in
voltage clamp (VC) and current clamp (CC). In contrast to standard patch clamp amplifiers the
electrode voltage is nevertheless measured, also in VC. However, due to current flow during voltage
measurement, this measurement is distorted by the series resistance. This is the reason why the linear
mode should be used only for recordings where only little current flows.
In the linear mode the background noise of the amplifier is substantially reduced. Therefore, the linear
mode is predestined for low-noise recordings in VC and CC mode.
The linear mode allows also l
oose-patch or macro-patch recordings, and can be used to approach the
cell and form a gigaseal in VC mode.
The LIN x10 mode can be used for iontophoresis or electroporation, i.e. juxtacellular, non-invasive
filling of cells with or single cell transfection with DNA. The stimulus amplitude range in CC or
BRIDGE mode is also enhanced to max. ±120 nA.
Operation
The linear mode is set through the Linear Mode switch at the front panel. When the switch is set to the
middle position, the amplifier is in “switched” (VC or CC) or in BRIDGE mode (CC). Setting the
switch to x1 or x10 lets the amplifier work in linear mode either without or with x10 amplification.

Linear Mode - x1/x10 switch
x1: The amplifier operates in linear, unswitched mode (see below), current and/or
voltage are not enhanced. LIN LED lights green.
x10: The amplifier operates in linear electroporation mode. Command voltage in VC or
current stimulus in CC or BRIDGE mode are multiplied by the factor of ten. This
allows to apply stimuli of max. ±120 nA. In this operation mode the LIN LED lights
red and the voltage output at POTENTIAL OUTPUT x10mV BNC connector is set
to
x1mV.
middle: In the middle position of this switch the amplifier works in switched or BRIDGE
mode. The LIN LED does not light.
Important : In LIN x10, the voltage output (POTENTIAL OUTPUT x10 mV BNC connector) is set to
x1 mV , i.e. 1 V is 1 V (and not 100 mV as in LIN mode x1).
Important : The linear mode must be used with low resistance patch pipettes only! Ringing can be
avoided by setting the GAIN in VC mode not higher than 1 and by setting the capacity compensation
of the electrode to very low values (best close to zero).
Note : Be always aware, that the linear mode introduces a series resistance error that is dependent on
the magnitude of series resistance and current that flows during measurement.
Important : The LIN mode x1 or x10 must not be used if two SEC amplifiers work in synchronized
(Master/Slave) configuration.
Important : BRIDGE balance and Capacity Compensation work in LIN mode and can be used to
minimize artifacts during electroporation.