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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CMOS Driver (CB13776E)
This circuit is from a 1976 Motorola CMOS manual. It can be implemented with modern Darlingtons like...
Voltage Controlled Unijunction Oscillator (CB4432E)
In the figure we have the way of modulating or controlling the frequency of a relaxation...
Alternator Monitor (CB15050E)
The purpose of this circuit is to monitor the operation of an alternator in cars with a 12 V...