Indicated for the protection of three-phase systems, this circuit was found in an American documentation of the 70's. The circuit can be implemented with modern components.
We found this circuit in the Philips integrated circuits manual of 1990. The basic component is...
This circuit of a 73 American magazine from the 1990s can generate multiple frequency signals from the...
This circuit is from old documentation but can be applied to modern equivalent components. The...