Circuit for connecting load to one of two different mains voltages - uses relay to automatically switch supply to appropriate load supply terminals according to supply voltage magnitude

摘要

The circuit connects a supply voltage to either the high voltage or low voltage input terminals of an electrical apparatus according to the magnitude of the supply voltage. In its rest position a selector switch (13) connects the high voltage terminals of the land (12) to the supply voltage. The circuit has a voltage dependent switch which when the lower supply voltage is applied, automatically switches over the selector switch (13) to the lower voltage load input voltage terminals (11). The selector switch may be a relay.