Touch sensor (CB8723E)

Found in a 90s Popular Electronics, this circuit uses two PLL tone recognizers to trigger by touch an external load.

| Clique na imagem para ampliar |

LM386 Oscillator (CB24988E)
Circuits like this one, using the LM386 audio amplifier, are available from other sources in this...
Passive Tone Control (CB12206E)
This bass and treble control only attenuates the corresponding signals, requiring further...
LC Audio Oscillator (CB8082E)
Using a large inductance, this circuit was found in a Popular Electronics from the 90s. The...