PHOTOELECTRIC SWITCH

摘要

A semiconductor switching device for use in high voltage applications (typically ranging from 5kV up to about 50 kV) makes use of the well-known effect of reverse conduction in silicon diodes when exposed to light. Hitherto, photodiodes have been commercially available for relatively low voltage applications. The device disclosed herein is implemented by a high voltage diode (10) comprising a series of semiconductor junctions and a light emitting diode (12) operable to irradiate the junctions to render the high voltage diode conducting in the reverse bias direction, the high voltage diode and the light emitting diode being supported in fixed predetermined relation within an encapsulating material transmissive to the radiation emitted by the LED. The switching device finds application in electrostatic spraying devices where the current demands are relatively small, e.g. up to about 2 mu A , and is used for controlling high voltage production, distribution and/or shock suppression.