This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
New Low-Power PIC24 “GA7” Microcontroller Family Now Available CHANDLER, Ariz., Dec. 12, 2016 — The...
The purpose of this receiver is to monitor the signal from a nearby transmitter. It was published in an...
The LM567 is a PLL tone decoder that can also be used as a double oscillator as shown in the...