Single-channel current simulation and recording using a photodiode as current generator.

A device which can generate rectangular currents in the picoampere range is described. The current generator is a photodiode connected to the head stage of a single-channel recording amplifier. The photodiode is activated by a light-emitting diode controlled by a computer or any other current source. The device can transmit signals corresponding to simulated single-channel behaviour. Since the kinetic parameters of the simulation are known, the user can test the data acquisition and analysis system under conditions similar to those prevailing during recording from a biological membrane. This current generator can also be used for the tuning of patch-clamp amplifiers; rectangular currents generated by the photodiode allow the frequency response of the amplifier to be properly adjusted.