Abstract: A power supply for standby circuits for an electrical consumer which separates both the electrical consumer and the power supply from the mains when in standby mode. The necessary power is supplied by a storage component backed up by an alternative voltage source. A voltage detector monitors the state of charge of the storage component and connects the circuit of the power unit to the mains as necessary. This power supply is suitable both for standby circuits of electrical consumers and for devices themselves or simply for control components and remote-control receivers on devices. Since a power unit is only connected to the mains when necessary, considerable energy savings are achieved.