Battery charger (CB9121E)

Found in an Electronics Now from the 1980s, this circuit uses some components that are still common today. For others, equivalents can be tested.

| Clique na imagem para ampliar |

Bistable Multivibrator (CB9925E)
This circuit using an operational amplifier was found in old American documentation. It can be...
Simple transistor tester (CB23746E)
If the circuit oscillates, emitting sound, it is because the transistor is good. This simple...
Telephone Amplifier with TDA7052 (CB990E)
Like the previous circuit, this is used in the analog part of the telephone lines. The same...