Dagan IX2-700, Руководство по эксплуатации

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IX2-700 Dual Intracellular Preamplifier
5
OFFSET VOLTAGE CONTROL
This control cancels electrochemical potentials developed between reference
electrodes and the probe input. Offsetting the output level of the amplifier nulls
these potentials. The range is ±200 mV. Be careful not to touch this control during
the experiment, as it will change the baseline.
ELECTRODE IMPEDANCE TEST (Z TEST)
This switch provides a rapid check of electrode impedance. When switched
on, the square wave signal proportional in amplitude to the electrode impedance,
appears at the 10 VmBNC connector. A signal level of 1 mV is equivalent to 1
Megohm of electrode resistance when using a X1 headstage. A X.1 (i.e., divide by
10 headstage) scales this to .1 mV per megohm referred to the input.
DC CURRENT 10-TURN DIAL
The current dial provides a depolarizing (positive) or hyperpolarizing
(negative) current selected by the corresponding Positive/Off/Negative polarity
switch. The range of the current is 100 nA full scale times the headstage multiplier.
Thus, the X .1 headstage would change the full scale dial reading to 9.99 nA. The
current control is linear and the readout corresponds to the actual current selected.
This current is algebraically added to the currents produced by the EXT I BNC
connector and also the Step Current Command Generator, if selected.
BRIDGE BALANCE CONTROL
The bridge Balance Control is used to null out the effects of stimulus current
passing through the recording electrode. The bridge is balanced by turning the
knob on the dial housing. When the bridge is balanced the voltage seen at the
10Vm connector will be nulled to zero and the resistance of the electrode and cell
membrane is read on the dial. The range of the bridge balance dial is 100
Megohms divided by the probe current multiplier. Thus, for the X.1 probe, the
range will be 1000 Megohms. The bridge Balance is disabled when Z Test is used.
STEP CURRENT 10-TURN DIAL
The step current adds to the Holding Current and has ten times the range. It
can be on continuously, if gated on and off by a greater than 3 volt level supplied
to the Gate BNC connectors.