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 a 90s Popular Electronics, this circuit is based on a common CMOS component. The circuit...
Taken from an Electronics Now from the 90s, this circuit generates signals whose frequency depends on...
This power supply uses a single-winding transformer. We found it in July 1984 Radio Electronics magazine....