This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
The transmitter can be that of CB9574E. This receiver uses a PLL to directly trigger a sensitive relay....
This circuit can be used in alarms to generate a warning signal. The circuit is from a 1960s...
Author: Newton C. Braga Published:August 1, 1998 Formato:Book and e-Book Pages:...