Fast microelectrode headstage for voltage clamp
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Fast response in microelectrode recordings may be made by measuring the current through a microelectrode, rather than the voltage. Current recording keeps the electrode at virtual earth and thus prevents the loss of high frequency response owing to charging of the electrode capacity through the tip resistance. We describe a circuit which is a combination of current and potentiometric recording. For high frequencies the amplifier functions in current mode, and for low frequencies in potentiometric mode so that there is no average load on the cell. The amplifier rise time is less than 5 microseconds, is stable, quiet and requires no high frequency compensation.
KeywordsAmplifier Microelectrode Voltage clamp
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