This circuit is from a 1967 documentation. It consists of a sensor for memories used at the time. It can be made with modern equivalent transistors. Note the 4 V symmetrical power source.
In the figure we have the configuration of the circuit as a conventional Darlington. In this...
This circuit provides a signal when dialing occurs. The circuit is powered by the telephone line...
Using an RCA CA3018 as a base, this circuit has a sensitivity of 2 Mohms per volt. The circuit is from a...