Abstract: The invention provides an image intensifier arrangement in which for each stage either the luminescent screen or the photo cathode thereof is decoupled by resistive decoupling with respect to the capacitances of a power supply source which is provided to supply high tension thereto. In each case the resistive decoupling consists of a resistor of such value as to provide a time constant with the capacitance of the relevant output point of the power supply which is many times greater than the duration of a typical high energy flash to which the intensifier is likely to be exposed in operation.

Abstract: The invention provides a multi stage image intensifier arrangement in which, for any stage, means are provided responsive to the photo current of the stage for discharging capacitance associated with that stage so as to limit the level of current density to which the anode screen of that stage is subjected as a result of a high intensity input flash of light.