SELF-BALANCED ACTIVE CURRENT BRIDGE FOR MEASURING THE IMPEDANCE OF AN EXTERNAL DEVICE

摘要

A self-balanced active current bridge for measuring the impedance of an external device or an output current, comprising an input potential source and operation amplifier connected to the input potential source via a first input terminal of the operation amplifier. A balancing bridge is coupled to a first output terminal and a second output terminal of the operation amplifier. A controlled potential source is coupled to the balancing bridge and used to maintain the balance state of the balancing bridge. A resistance is connected between the balancing bridge and an output terminal of the controlled potential source. Wherein the external device is connected a first node between the balancing bridge and a second input terminal of the operation amplifier. Wherein the controlled potential source is coupled to the balancing bridge to maintain the balance state, thereby constructing the self-balanced active current bridge for measuring the impedance of the external device or the output current by means of measuring the parameters of the resistance.