This 1968 circuit is intended to switch the polarization of a satellite TV antenna of the time. The circuit is powered by 12 V and the transistors are 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...