Elektronenblitzgerät

In an electronic flashlight unit, a controlled semiconductor rectifier is ignited simultaneously with the ignition of flash tube and power from a first capacitor flows therethrough. A voltage of one polarity thereby appears across the rectifier. The discharge causes a voltage drop across a resistor and that voltage drop is used to charge an integrating capacitor in correspondence with the integral of the flash light flux as detected by a photoresistor. At a predetermined integral value a switching action applies the voltage of a quenching capacitor across the rectifier in a manner such that the polarity is opposite to said one polarity. The rectifier is thereby turned off to ensure that the flash tube is quenched. In one embodiment two semiconductor rectifiers each connected in series to a reactor are provided in the flash discharge circuit and a second pair similarly connected in the quenching circuit to enable the use of inexpensive low-power semiconductor rectifiers protected from overloading.