With this system you can disconnect phone lines in case of need for protection. The circuit is from a 1989 documentation working only with analog lines.
This other high stability thermocouple amplifier uses an 80's operating. The circuit can be used...
The mains cables work as antennas. We can take advantage of them with this circuit that consists of a...
This circuit was found in an American magazine in 1976. It doubles the frequency of TTL signals in the...