Found in a 90s Popular Electronics, this circuit uses two PLL tone recognizers to trigger by touch an external load.
This circuit is old, from an English publication from 1979, so the indicated sensor is no longer...
This solid-state relay circuit (SSR) or shield is from a 1995 Electronics Now. With it we can...
Found in a 90s Motorola documentation, this circuit makes it a PUT. This component is not very...