Ammeter current to be measured deflects the moving magnet. Since the ammeter shunt has a very low resistance, mistakenly wiring the ammeter in parallel with a voltage source will cause a short circuit, at best blowing a fuse, possibly damaging the instrument and wiring, and exposing an observer to injury. In AC circuits, a current transformer converts the magnetic field around a conductor into a small AC current, typically either or at full rated current, that can be easily read by a meter. In a similar way, accurate AC/DC non-contact ammeters have been constructed using Hall effect magnetic field sensors. A
Becky Measures Becky Measures Becky Measures (born 13 October 1981 in Derbyshire, England), from Bakewell, Derbyshire, is a radio presenter on Peak FM, an independent local radio station in Derbyshire and a professional charity fund-raiser. She held a variety of jobs including being an extra for the locally filmed television series "Peak Practice" before moving into radio. In 2004, Measures, then 23, decided to have a double mastectomy after a genetic test revealed that she had an 80 to 90 per cent risk of developing breast cancer. Both her mother and a cousin, Helen, had suffered from the same illness. To help