Small phonographic amplifier (T1547E)

This small 1W turntable amplifier was found in the 1975 RCA tube manual. It is a commercial circuit at the time.

| Clique na imagem para ampliar |

ELF Monitor (CB21055E)
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
Controlled Oscillator (CB12682E)
We can use any type of resistive transducer with central resistance in the range of 10 k ohms to 1...
Triac Double Dimmer (CB16915E)
This circuit controls two lamps so that when one increases in brightness the other decreases. The...