An Automatic Voltage Clamp Recorder for Inexcitable Membranes

In order to clamp the voltage, to correct for solution resistance, and to record the short-circuit current (SCC) automatically in inexcitable biological membranes, three independent units are usually needed: a voltage control unit, a subtracting amplifier, and a recorder. A circuit has been devised in such a manner that one servo recorder performs these three functions. It consists of a constant current supply with a network including a ten-turn potentiometer (10-T-P) which controls and makes the amount of current delivered to the membrane linear to the position of the 10-T-P slide arm.