This amplifier for recording heads was found in a Radio Electronics from September 1963. The circuit uses period transistors but can be modified to work with modern transistors.
Based on an integrated circuit CA31062 which consists of a photosensor, this circuit was obtained from...
This ultra-simple meter uses an output transformer and a small speaker as a microphone. The...
The frequency of this oscillator depends on the crystal used and the transistors. The circuit was...