3.1 Two-electrode voltage clamp using microelectrodes.3 Variations of the voltage clamp technique.The voltage clamp allows the membrane voltage to be manipulated independently of the ionic currents, allowing the currentвЂ“voltage relationships of membrane channels to be studied. Cell membranes of excitable cells contain many different kinds of ion channels, some of which are voltage-gated. Because the currents applied to the cell must be equal to (and opposite in charge to) the current going across the cell membrane at the set voltage, the recorded currents indicate how the cell reacts to changes in membrane potential.

This 'clamps' the cell membrane at a desired constant voltage, allowing the voltage clamp to record what currents are delivered. A basic voltage clamp will iteratively measure the membrane potential, and then change the membrane potential (voltage) to a desired value by adding the necessary current. The voltage clamp is an experimental method used by electrophysiologists to measure the ion currents through the membranes of excitable cells, such as neurons, while holding the membrane voltage at a set level. This signal is amplified and output is sent into the axon via the current-passing electrode. The membrane potential amplifier measures membrane voltage and sends output to the feedback amplifier this subtracts the membrane voltage from the command voltage, which it receives from the signal generator. The voltage clamp operates by negative feedback.

Voltage vsamp