Phone circuit (CB8709E)

With this circuit, found in a 80s Popular Electronics, it is possible to use two ordinary phones in a basic intercom.

H bridge with MOSFET (CB21098E)
This circuit, which appears elsewhere in this section, was taken from McGRAW documentation from...
Modulator TDA2002 (CB18091E)
This modulator circuit can be used in AM transmitters up to about 10 W of power. The TDA2002 must...
Sampling and Holding (CB19700E)
This circuit with low-slip characteristics uses an operating system that is not very common today....