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 |

Slow Turn On Power Supply For Amplifiers (CIR815E)
This circuit is used to cut the “click” in the loudspeaker of amplifiers when they are turned on....
Crystal calibrator (CB6900E)
This circuit for several frequencies was obtained in an American documentation from the 90s. The...
Audio Output Stage (CB466)
This simple circuit can be used as audio output stage for intercoms, experimental radios and other low...