On off


Push Off Push On

The ubiquitous 555 has yet another airing with this bistable using a simple push-button to provide a push-on, push-off action. It uses the same principle of the stored charge in a capacitor taking a Schmitt trigger through its dead-band. Whereas the Schmitt trigger in that reference was made from discrete components, the in-built dead-band arising […]


On And Off Button

In this simple circuit we give the chip a little more attention than usual. It is astonishing what can be built with a 555. We are always infatuated with simple circuits using this IC, such as the one shown here. The 555 is used here so that a single push-button can operate a relay. If […]


Laser Controlled ON – OFF Switch

This circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a controlling device. A laser pointer, now easily available in the market, can be used to operate this device. This circuit has been tested in operational […]


555 Timer Circuit With Variable On/Off Times

This circuit enables the on/off times of a 555 timer to be independently varied over a wide range. This is not possible with a conventional 555 circuit with the RC network being charged from the positive supply rail and discharged via pin 7. Instead, the capacitor at pins 2 & 6 of IC1 is charged […]