Found in a 90s Popular Electronics, this circuit allows to select the operating ranges between short waves and VHF. MOSFET is uncommon today.
This circuit was obtained from an English circuit manual. Components are common and LEDs can be 3...
Found in a 90's EDN, this circuit generates signals in the frequency range given by the graph. The...
This circuit can generate signals from 100 kHz to 1 MHz depending on the L1 coil. For the medium...