Solar timer (CB20498E)

This very low consumption circuit can be powered by a solar cell. The time indication is given by a microammeter.

2-Tone Siren (CB18189E)
Because it uses TTL integrated circuits, this siren must be powered by 5 V or as indicated with D1 to...
Speaker Circuits (CB16349E)
The correct connection of speakers and tweeters in a speaker to obtain better sound quality,...
Schmitt trigger 40106 (CB21565E)
The CMOS PLL used on this circuit is not very common. The circuit can be used to take out contact...