This novel buzzer circuit uses a relay in series with a small audio transformer and speaker. When the switch is pressed, the relay will operate via the transformer primary and closed relay contact. As soon as the relay operates the normally closed contact will open, removing power from the relay, the contacts close and the [...]
This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. It has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. It is connected permanently to the 12-volt supply and its operation is “enabled” by opening SW1. By using the expansion modules, you can add as many zones [...]
This is Easy and Mini Timer Circuit ( Egg Timer) by IC 555.
Alarm by Buzzer.
Read more : Circuit Egg Timer By 555
Other Link
Circuit Door Buzzer by NE555 + LM386
Timer with buzzer and optocoupler by IC 4060
Light Detector by IC CD4001
Obsession Theme by Lorelei. Coded by Cheap web hosting and Hostmonster.
Featuring Liza Kliko's artwork in the header.
