This power source was found in a Motorola manual from 1968. Transistors are from the era, and current equivalents can be used.
This high-gain circuit was found in an American publication from the 1990s. The circuit can use...
This circuit automatically controls the degree of illumination. As the circuit is from 2001, it...
This circuit was found in a Radio Electronics from April 1990. The circuit has 5 equalization...