Assertion: mag meter | /r/Desires | ac or dc electricity
Facets:
value: from a power line
type: TRANSITIVE-OBJECT
value: from battery
type: OTHER
value: to operate the electromagnets
type: PURPOSE
Source sentences:
text: Mag meters use the physics principle of Faraday's law of induction for measurement and require AC or DC electricity from a power line or battery to operate the electromagnets.