This circuit synchronized by the power grid can be used as a shield. We found it in an 80's Electronic Engineering. R1 can typically be 4k7.
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...
) Suggested by Philips in a 1968 documentation this circuit has very high 10 ohm on-load voltage...
No information is given about the transformers in this circuit suggested by Motorola in a 1968...