This commercial transistor radio was manufactured by RCA in the 1960s. The circuit has only 4 transistors and is powered by a voltage of 9 V with an audio power of 20mW.
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...