IX2-700 Dual Intracellular Preamplifier
4
CONTROL DESCRIPTION
3.5 DIGIT LCD METER
The meter has five functions. They are:
(1)
Measuring the Channel 1 output voltage at a gain of one (i.e. I Vm)
(2)
Measuring the Channel 2 output voltage at a gain of one (i.e. 1 Vm)
(3)
To measure the potential difference between Channel 1 and Channel 2.
(4)
To measure the membrane current Im from Channel 1 scaled by the
headstage for automatic decimal point on the meter.
(5)
To measure the membrane current Im from Channel 2 scaled by the
headstage for automatic decimal point on the meter.
BUZZ OPERATION
The buzz or tickle function contained in the IX2-700 is used to impale an
electrode in the cell. The IX2-700 has a controlled buzz magnitude. Start with the
Buzz Magnitude in the counterclockwise or minimum position and increase while
initiating buzzes until you achieve desired cell penetration. (Buzz magnitude is a
trimpot located under the buzz switch).
CAPACITANCE COMPENSATION CONTROL
This control provides input capacitance neutralization. Without this
compensation high frequency signals from a high impedance source such as a
micropipette would be lost because of stray capacitance at the input. Start with this
control at its minimum in the counterclockwise position.
The amount of capacitance compensation available depends on the
capacitance compensation range ordered with the probe you are using. Ranges as
small as 15 pf and as large as 100 pf are available (35 pf standard). Smaller ranges
produce less noise and are ideal for very low capacitance microelectrodes used
with high switching frequencies. The larger capacitance compensation ranges are
ideal for doing typical bridge preamplifier procedures and also switched single
electrode voltage clamping in deep tissue, where the microelectrode has a high
capacitance associated with it.
