An electrical circuit for charging a DC voltage source from an AC voltage network. The circuit includes an input that is able to receive an AC voltage from the voltage network, and a first output able to be connected to the DC voltage source. An insulating stage formed using a plurality of capacitors is arranged so as to electrically insulate the input from the first output of the circuit. A frequency-raising stage is arranged between the input of the circuit and the insulating stage so that the capacitors of the insulating stage are in a circuit portion that has flowing through it an AC current at a frequency that is greater than that of the AC network.