An apparatus equipped with a battery, such as an electrical toothbrush, receives from a charging device a charging voltage which adapts to the charged condition of the battery and on whose over-discharging is correspondingly small. On the one hand the apparatus comprises a series circuit between a capacitor and a diode which is connected to the charging device parallel to the battery, wherein the diode is arranged in the forward direction. On the other hand in series to the battery there is arranged an electronic switch which periodically for a short time interrupts the charging procedure of the battery. In each case during such an interruption the charging apparatus is unloaded and its voltage increases jump-like by which means the capacitor can be charged via the diode. In each case with a closed switch, i.e. on loading the charging apparatus by the battery, the capacitor supplies a further relatively high impedance load so that this independently of the value of the charging voltage may be supplied with a sufficiently high and constant voltage.