This toy transistorized organ was found in the May 1970 issue of Radio Electronics magazine. The trimpots are adjusted to the musical notes according to the key.
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...