This interesting digital counter with relays with complementary outputs was found in the Radio Electronics magazine of October 1961. The supply voltage is in accordance with the relays used.
This simple transistorized radio for listening on a crystal phone was found in a Japanese...
This very high voltage generator (VHV) uses a 555 and a power transistor with a heat sink. The...
Found in a 1969 documentation, this circuit is reset by a push button. The activation time is 100...