This crystal-based circuit can generate accurate 50 or 60 Hz signals. The circuit is from a November 1998 Electronics Now magazine. The output signal consists of rectangular pulses.
This General Electric circuit is from the 80's. The PUTs used in this meter are not common...
This circuit provides a power of the order of 2 W, characterized by high performance. The output...
The sensor can be made using two bare wire or two screen with a piece of tisse between them. One...