This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a frequency determined by R and C. The selection by the jumpers determines the PWM modulation.
This circuit was taken from a Popular Electronics from the 1990s. The circuit triggers a relay that...
Found in a Popular Electronics from the 90s, this theremin is played by the position of the hand...
We found this circuit in a transistor manual from the 1960s. The transistor is the Germanium...