This receiver was found in a Popular Electronics from the 90's. Its different configuration shows a tuning circuit after the tube that works as an aperiodic amplifier. Observe supply voltages.
This circuit is one of many that the reader can find in this section for testing crystals. The...
This circuit was found in a Philips documentation from 1966. Its purpose is to drive the solenoid...
This sinusoidal oscillator is suggested by Texas Instruments' Linear Circuits Applications, using a...