Electronic flash equipment

摘要

The unit comprises a charging control circuit which is a solid state switching circuit effective to delay the recharging of main flash tube capacitor or capacitors, after discharge through the flash tube A, to allow the flash tube to quench completely. When capacitors B discharge through the tube A, capacitor C discharges rendering transistor G conductive and transistor F nonconductive so that triac D cannot conduct in the negative phase of the AC cycle. The similar components C', G' and F' prevent triac D conducting in the positive phase of the cycle thus the main storage capacitors B are not recharged until the charge on C, C' is dissipated. The same solid state switching circuit can be used to stabilise the voltage on the flash tube capacitors B at any of a number of desired charge levels. The flash tube A can be mounted with a tungsten-halogen lamp 33 in a single housing.