This circuit was found in the May 1984 issue of Radio Electronics magazine. It analyzes the exhaust gases emitted by a car. The circuit uses a special gas sensor from that time.
Because it uses TTL integrated circuits, this siren must be powered by 5 V or as indicated with D1 to...
The correct connection of speakers and tweeters in a speaker to obtain better sound quality,...
The CMOS PLL used on this circuit is not very common. The circuit can be used to take out contact...