The invention provides an electrical device with a current-limiting circuit, comprising a power transistor and a current-limiting device, wherein a ratio of the width to the length of the power transistor is determined by the maximum load current of the electrical device. The current-limiting device also comprises a second transistor and a voltage drop control unit, wherein the voltage drop control unit is regulated to ensure that a second potential difference needed by the current-limiting circuit is equal to output currents of the power transistor and equal to a first potential difference ofa source electrode potential and a grid potential when a current value is limited; and the second potential difference is equal to a potential difference of the grid potential of the second transistor and a first voltage. The invention also provides the current-limiting circuit.