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.

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SCR Power Control (CB4678E)
This is a slightly different configuration of full-wave power control than we found in an old...
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This 1-transistor timer was published in Radio Electronics magazine in December 1960. The circuit has...
Automatic speed regulator for DC motors (CB23722E)
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