Usually in the literature I’ve seen long list of rules about doing stuff with mains first and example circuit after that. ... If you need more than 50mA of current, then get a transformer.

Unlike the voltage transformer, a current transformer measures current from one circuit to another, which requires different calculations to create the optimal design. Current transformers measure ...

Nikola Tesla - A New System of Alternate Current Motors and Transformers, ... A motor with one of its circuits in series with a transformer and the other in the secondary of the transformer. 2.