This two-digit (up to 99) circuit divides a signal by values programmed by the BCD switches. The circuit comes from a Radio Electronics from February 1989.
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,...