Pulse Generator

This circuit is very useful while checking/operating counters, stepping relays, etc. It avoids the procedure of setting a switch for the...

Automatic Gate Light With A Musical Bell

This circuit may be used to auto- matically switch on a light at the enterance gate to a premises, at night, by sensing the presence of a pe...

Birdie Doorbell Ringer

Notes P1 is of experimental value. Start with 220 Ohms or so and modify to suit your needs. The transistor is a general purpose kind and is ...

Ultrasonic Dog Whistle

It's well known that many animals are particularly sensitive to high-frequency sounds that humans can't hear. Many commercial pest r...

'Beeper' Using 1C 555

Here is a 'beeper' circuit employing two 555 ICs. It can be used in various circuits (having supply voltage of 5 to-15V DC) that req...