This simple and cost-effective ding dong electronic doorbell circuit is based on IC 8021-2. The IC has an in-built circuitry to produce ding dong sound each time its pin 3 is pulled low. The sound is ...

If you’re expecting an important visitor but you just have to step out for a moment, an electronic doorbell memory can come in handy so you can see whether someone rang while you were out. Of course, ...