Ammeter through a wire which expands as it heats. Although these instruments have slow response time and low accuracy, they were sometimes used in measuring radio-frequency current. These also measure true RMS for an applied AC. In much the same way as the analogue ammeter formed the basis for a wide variety of derived meters, including voltmeters, the basic mechanism for a digital meter is a digital voltmeter mechanism, and other types of meter are built around this. Digital ammeter designs use a shunt resistor to produce a calibrated voltage proportional to the current flowing. This voltage is then measured by
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