This small 1W turntable amplifier was found in the 1975 RCA tube manual. It is a commercial circuit at the time.
This small transistor amplifier was found in an ancient American documentation. Transistors can be replaced...
In the figure we have the way to use a common LED as a light sensor. The operational power supply...
This circuit was obtained from an 80's Radio Electronics. The circuit decodes “scrambled” or...