Where can I get design for an alarm annunciator?

Question

Sagar E.

Answer 1

That depends on what you want it to do?

Most alarm annunciators will cause a light to illuminate and/or a tone to sound when some condition occurs. This can be as simple as providing power to an LED and powering a Sonalert piezo alarm. To do this may require an open collector transistor or FET driver or a relay, but either way there must be some circuit involved in making the decision to enable the alarm. This is likely a microcontroller or microprocessor device which enables its pins when the alarm condition has occurred. The pins on some microcontrollers can directly drive an LED with series resistor, so this would be simplest annunciator.