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 ...

[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 ...

Battery level indicators generally detect the voltage levels of the batteries to give a result. So, tester circuits must not be a heavy load during the measurement process. This tester circuit draws ...