When the phone rings, a high-powered incandescent light comes on. This circuit can be interesting to obtain the remote call warning or to assist the hearing impaired.
We found this protection circuit for the power supply in a 1992 documentation. This circuit has...
I found this circuit in a documentation for radio amateurs from 1975. The FET could be the BF245....
Found in an American 80's documentation, this circuit can use common FETs like the BF245 and cover...