4-tube reflex (T1662E)

This circuit that uses a loop antenna was found in a 1924 publication. The circuit has several supply voltages and sets of audio and RF coils.

| Clique na imagem para ampliar |

Servo amplifier (CB23814E)
This circuit can be adapted to be used in a follow the line robot. It was found in the May 1962...
Headphone adapter as equalizer (CB23842E)
In the figure we have adapter circuits for using stereo headphones in an amplifier without a...
Tremulo circuit (CB10115E)
This circuit was found in a National Semiconductor manual from the 1970s, appearing in articles and on...