The invention relates to a circuit assembly for operating a luminous signal, particularly an LED signal, comprising at least one light-emitting diode (D) to which a resistance (R) is serially connected and a control (St) is connected in parallel. In order to adjust the luminous power of the luminous signal to various degrees of brightness during the day and at night, the control (St) is provided with a controlled source of current so as to specify a parallel current (I_P) which reduces the current (I_D) flowing through the light-emitting diode (D).