This traditional configuration found in a Radio Shack document can use 2N2646. More keys can be added, and the power can be supplied with voltages from 9 to 15 V.
Found in documentation from the 70s, this circuit uses an operational one from that time. It goes for...
This circuit is based on uncommon operations today but can be adapted to operate with more modern...
These correspond to the short-wave bands from 7 to 14 MHz, occupied by both commercial and radio...