When working around mains voltages, it can be useful to know whether a given circuit is live or not. While this can be done by direct connection with a multimeter, non-contact methods are available ...

In multiple-output power supplies in which a single supply powers circuitry of vastly different current draws, two perplexing steps are sensing the current that each output draws and deactivating the ...

[Dino] is back with another installment of his Hack a Week series, and in this episode he is taking on what he promises will be the last transistor-based project – at least for a little while. In the ...

This is a very simple liquid detector that use a relay to open an evacuation van. You can use it for water or any liquid that conduct electricity. Use any PNP transistor that can stand the relay ...