Stereo preamplifier TDA3410 (CB21937E)

Taken from the 1982 SGS manual on integrated circuits, this preamplifier was used in commercial equipment at the time.

Rail indicator for modeling (CB21084E)
Found in Popular Electronics from the 90s, this circuit uses a reed switch on the rails as a...
4 to 20 MHz XTAL 1 transistor oscillator (CB16100E)
This oscillator does not carry any resonant circuit, except for the one formed by the crystal...
Piezoelectric Transducer Beeper (CB15762E)
The circuit shown in the figure causes a piezoelectric transducer to emit interval beeps. The 100...