Timed switch for an AC load
AssigneeCanadian Patents & Dev. Limited
InventorsAlan W. Levy, Attila J. Szanto, Peter C. Wheeler
Life of this patent
Estimating the term…
Abstract
The timed AC switch comprises a manual on-off switch in series with bidirectional semiconductor switch, such as a triac, for connection in a loop with an AC source and a load which would generally be incandescent or fluorescent lamps. The semiconductor switch is driven by an RC oscillator which is under the control of an inhibit circuit and a digital counter which itself is driven by the oscillator. The counter is reset at initial start up, and may also be reset while operating or after counting out. The times switch may also be controlled to inhibit the oscillator for a very short time as a warning before finally timing out.
Claims9
A timed AC switch comprising:
- manual switch means having an on and an off position;
- bidirectional semiconductor switch means connected in series with the manual switch means for connection in series with an AC source and a load;
- oscillator means coupled to the bidirectional switch means having a frequency greater than the AC source for controlling the conduction of the switch means;
- timing means for providing a different timed output signal on each of a number of output leads;
- and
- inhibit circuit means selectively coupled to at least one of the timing means output leads to inhibit the oscillator means at the preselected time.
Dependencies are inferred from the claim text.