This basic circuit showing the LM3914 “inside” was published in the October 1980 issue of Radio Electronics magazine. Note that R1 determines the brightness and that the power supply is 9 V.
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...