Category Archives: Circuits

Cellphone Operated Toggle Switch

Aussiemike in Kenya – who suggested that light from a mobile phone’s display screen could be used to trigger a switch. When a brief (free) phone call illuminates the display – the light from the display operates a 4017 based Toggle Switch. And any small push switch – connected in parallel with the LDR – will provide optional manual control.

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Toggle Switch No.2

Pushing the button once will energize the relay. Pushing it a second time will de-energize the relay. Any simple momentary action push-to-make switch will do. The prototype has a single-pole relay. But you can use a multi-pole relay if it suits your application. The circuit will work at anything from 5 to 15-volts. All you need do is select a relay with a coil voltage that suits your supply.

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Repeating Timer No.8

This circuit energizes the relay repeatedly – at regular intervals. The length of the intervals depends on the setting of R4 – and the output pin to which the “Range” wire is connected. With the range wire connected to pin 3 – intervals of up to 24-hours are available. If you need longer than 24-hours – increase the value of C3.

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