This small 1W turntable amplifier was found in the 1975 RCA tube manual. It is a commercial circuit at the time.
This oscillator takes advantage of the 2000 ohms headphone inductance as the oscillator circuit coil....
This circuit was found in an 80's Electronic Engineering. The circuit uses a multivibrator with...
Found in a 90s Radio Electronics, this circuit is intended to trigger a relay when the current in...