This unit prevents the Two-Zone Alarm from activating a second time. The siren will sound only once. So it can't become a nuisance.
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One-Time-Only Module

Free Circuit



The One-Time-Only Module prevents the Two-Zone Alarm from activating a second time. So the siren will sound only once - and it won't become a nuisance. This doesn't mean the building has to remain entirely unprotected. Anything connected to the module's output terminals - will continue to operate after the siren has been silenced.

The output terminals will comfortably supply up to about 250mA. So they can be used directly to power a strobe light - an internal siren - or even a small auxiliary internal alarm system. If you need more power - or you just want to control say the internal and/or external lighting - you can connect one or more relays to the output terminals. Relays will allow the module to control just about anything you like.

Schematic Diagram

There's nothing special about the SCR. Apart from current, voltage and power ratings - all thyristors are pretty much the same. So you'll probably find that practically any type of SCR will work fine. But you will need to check the pin configuration of your SCR. It may be different from that of the TICP106D.

Stripboard Layout

Photograph Of The Prototype


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