Found in the April 1995 issue of Electronics Now magazine, this circuit provides an output voltage that is three times the supply voltage. The current is very low.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...