Mini Organ (CB21653E)

This toy organ was found in Popular Electronics from January 1967. It can be constructed from modern equivalent transistors.

RIAA Transistor Amplifier (CB19171E)
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
Instrument Scale Modifier (CB4159E)
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Chime delay (CB9679E)
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...