PC-505B Manual, Rev. 201013
Warner
Instruments
A Harvard Apparatus Company
11
Series R
Series resistance compensation is used to compensate for the voltage drop across the
electrode and access resistance in the experimental setup. This control is used to adjust the
time constant of the
C
–
SLOW
control facilitating measurement of membrane resistance which
can be read from the dial.
This control is not available in single channel recording mode since series resistances
are negligible when compared with cell membrane and single channel resistances.
% Correction
% Correction is used to apply voltage compensation to the amplifier to correct for the
voltage drops due to the series resistance. This control is adjusted until the output signal
just begins to oscillate at the leading edge (ringing) of the
TEST PULSE
during experimental
setup. The control is activated by a toggle switch.
Leak subtraction
Leak subtraction is used to compensate for leakage currents to the bath through the
pipet/membrane seal resistance (RS) or through the membrane patch. For ‘leaky’ seals (RS
~1 G
) it is important to correct for the error caused by the shunt resistance of the leak.
This error can usually be ignored with ‘tight’ seals (RS ~10
to 100 G
). Fully
counterclockwise rotation of this control switches it off.
NOTE: Do not use
LEAK SUBTRACTION
if using %
CORRECTION
in whole cell mode. The
interaction between these two controls can introduce a systematic error into your data!
O
UTPUT
command block
The
OUTPUT
command
block
contains controls for selecting different
operating
modes
and
headstage
resistors. The instrument gain and filter
controls can also be found here.
Probe resistor select
The headstage resistor is selected
with the
PROBE RESISTOR
select switch.
The
high
position selects the 50 G
resistor for both patch and bilayer
headstages (models
LC-201
,
HC-202
,
and
HB-205
,
respectively). The
low
position is
used for whole cell recording and selects the 500 M
resistor in the
LC-201
headstage and the
50 M
resistor in the
HC-202
headstage. It is not available in the
HB-205
headstage.
The low resistor is automatically selected when in current clamp mode,
