Circuit Project Electronic

A time delay relay is a relay that stays on for a certain amount of time once activated. This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay. The time is adjustable from 0 to about 20 seconds with the parts specified. The current capacity of the [...]

This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used, and a simple voltage doubler drives a pulsating ultra-bright LED: current drawing is less than 500µA. An optional [...]

Linear scale - Small size
40 to 208 beats per minute
* Q1 & Q2 provide linear frequency operation of IC1 following P1 resistance variation.
* Q3 was added in order to obtain a louder click, similar to clockwork metronomes.
* A 12V micro [...]