Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

Triac Control Without Hysteresis (CB5275E)
This circuit was found in an American documentation from the 90's. The circuit can use almost any...
Comparator Photo Sensor (CB11588E)
This circuit triggers a relay when light strikes a sensor. The sensitivity is adjusted in the...
Simple Battery Charger (CB13191E)
We found this circuit on the internet, but it has some problems. It will be convenient to limit the...