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.
The LM143 integrated circuit is a high voltage operational amplifier from National Semiconductor that is...
This power supply can provide 10 A currents. Its regulation is made by 7812 integrated circuit. The...
We found this circuit in the November 1992 Radio Electronics magazine. It works with both...