NOVELTY - The device (D) has a control unit (MC1) generating an analog signal (s1) when a multiplexed communication network (RC) e.g. vehicle area network, is in a wakened state, an electrical equipment (EV) e.g. night lighting system, is used, and voltage (V1) is greater than threshold. The control unit generates another signal (s2) when the network is not in wakened sate, and equipment is used. Another control unit (MC2) supplies another voltage (V3). A third control unit (MC3) supplies the equipment with third voltage (V4) from rechargeable battery voltage (V2) on reception of the latter signal.    USE - Device for controlling voltage supply requirements of an electrical equipment of a car (all claimed) e.g. electric or hybrid car. Uses include but are not limited to controller, sensor, night lighting system and luminous ceiling light.    ADVANTAGE - The control unit supplies the electrical equipment with voltage from secondary source voltage on reception of the signal, thus avoiding useless consumption of energy when the vehicle does not operate and the equipment is not put in the non-operating state. The device avoids discharge of the main battery and secondary source and provides full autonomy, and is compatible with all electrical equipments such as controller that uses a direct and permanent power supply. The device does not require any modification of network architecture of electrical supply of the vehicle. The device is compact, flexible, and adaptable easily according to requirements. The device requires few components, and is inexpensive.    DETAILED DESCRIPTION - The control units are arranged in a form of analog multiplexer, and in a combination of resistances and transistors.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of a functional part of a system comprising a communication network, a main battery, an electrical equipment, and a control device.    Device for controlling voltage supply requirements of electrical equipment (D)    Electrical equipment (EV)    Control units (MC1-MC3)    Multiplexed communication network (RC)    Analog signals (s1, s2)    Voltages (V1-V4)