Busy Line Indicator (CB18711E)

This busy line indicator is very simple, serving for analog lines. The supply is made by two batteries and the transistors admit equivalents.

| Clique na imagem para ampliar |

CK722 Transmitter (CB23642E)
This small experimental transmitter with the CK722 transistors was found in Radio Electronics...
Direct Coupling Hearing Aid Amplifier (CB14760E)
We found this circuit in the old Mullard transistor reference manual from 1960. The circuit is...
Infrared Monostable Receiver (CB24831E)
This circuit is designed to be used with the infrared transmitter two circuits before this one....