This circuit was obtained from the April 1978 Radio Electronics magazine. The other circuit is a PLL of the time. The power supply must be 15 V symmetrical.
This circuit is from an Italian magazine Elettronica 2000 of September 1987. It is a pulsator for...
This voice-actuated bistable relay or sonic switch was found in English documentation. The circuit...
This circuit activates a relay when the sensor receives light indicating dawn. A relay with a 4k7...