Multi-voltage control for microfiche reader - uses chopper input to transformer having tappings and rectifier for various AC and DC LV supplies

摘要

The multi-standard control for the microfilm or microfiche reader has the lamps and blower operated on AC supply either directly from the mains or via a chopper circuit fed by a DC supply. The circuit incorporates a transformer with selected tappings so that a variety of AC and DC voltages can be used. No dropping resistances are required so that a versatile instrument is obtained, with a min. of power loss. This is esp. important for battery operation in the field. It can have a rectifier with a limiter to match the various DC voltages required for the 1. v use.