Telephone blinker

Posted on Nov 25, 2012

A small neon lamp is triggered into conduction by the telephone's ringing voltage, passes just enough current to activate the LED in optocoupler Ul, which in turn triggers the 6-A Triac that controls 12—a 117-Vac lamp or bell. (Capacitor Cl is necessary only when the circuit is used to drive a bell.) The lamp will flash off-and-on at the ringing rate, which is normally around 20 Hz.

Telephone blinker
Click here to download the full size of the above Circuit.

Ha 117 Vac bell is used, connect it in place of the lamp.

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