In use telephone indicator (CB9297E)

Found in a Popular Electronics from the 90's, this circuit is used to indicate the operation of telephones of the time. The circuit is TTL.

| Clique na imagem para ampliar |

12 V to 110 V Inverter (CB19043E)
This circuit was found in an Electronics Now of 1988. The circuit is still current, and the power...
Detectophone (CB14733E)
With this name, we found this electronic stethoscope with a coal microphone in a 1957 Raytheon...
Benchtop Amplifier (CB17490E)
This transistor amplifier with complementary symmetry configuration can provide approximately 1 W...