In order to avoid complicated power supply conversion and filter processing, and reduce the cost of the whole machine, an electromagnetic balance current sensor with single power supply is designed. The working principle of the closed-loop current sensor is adopted, a simple circuit is added on the basis of the closed-loop principle, a voltage stabilizing circuit is used for providing zero point output offset, a current signal to be measured is effectively and accurately expressed by a voltage signal in a linear mode, and the method can be used for detecting direct current, alternating current and pulse signals. The results show that the design is reasonable and feasible.