The present invention provides a circuit applied to a biopotential acquisition system, wherein the circuit includes an active current source and an amplifier. In the operations of the circuit, the active current source is configured to provide a current to two input terminals of the circuit, wherein the two input terminals of the circuit are coupled to two input electrodes of the biopotential acquisition system； and the amplifier is configured to receive input signals from the two input terminals to generate an output signal.本申請提供一種應用於生物電勢採集系統的電路，其中，該電路包括主動電流源和放大器。在該電路的操作中，該主動電流源被配置為提供電流給該電路的兩個輸入端，其中，該電路的兩個輸入端耦接于該生物電勢採集系統的兩個輸入電極，以及，該放大器被配置為接收來自該兩個輸入電極的輸入信號，以產生輸出信號。
