This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
Found in a 90s Radio Electrconics, this circuit is an operational one with a power stage using two...
Found in a 1969 Electronics World, this circuit is intended for amplifying analog cable TV...
This simple regulated power supply was found in a 1977 documentation. The zener diode determines the...