SCR Rain or Leak Alarm (CB22097E)

This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and the transistor a BC548.

Car Alarm (CB16911E)
This circuit uses unijunction transistors and drives a small speaker through an output...
Chopsticks Game (CB16438E)
This interesting game was found in a 1987 publication, but it is very simple and can be easily...
Temperature measurement bridge (CB23663E)
This circuit uses a thermistor or NTC as a temperature sensor and provides the indication on an...