This circuit switches on an external load after a certain interval given by the capacitor. The circuit is from a documentation from the 80s. The load depends on the relay used.
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...