Moving-iron instruments

These VA burdens are for moving iron instruments. For electronic meters these values would be of the order of 0.1 to 0.5 VA. 

State Ohm s law. Draw a labelled diagram of a moving iron instrument for the measurement of electric current. 

In medicine, a Bovie cautery device is an instrument used for electrosurgical dissection and hemostasis (stoppage of bleeding). It s like a soldering iron an electrical current is used to heat a treatment filament or a tip the tip becomes extremely hot and is then used to transfer heat to the tissue. The heat destroys the tissue or cuts the tissue if the tip is moved. The heat produced also stops any bleeding by burning small blood vessels. The device has limited use. It s not supposed to be used on the genitals. 

The main types of instruments are the nwving iron (d.c. and a.c.) (Fig. S.l 1), the permanent magnet moving coil (d.c. and a.c.) (Fig. S.12), and the moving coil dynamometer type (a.c.), all analogue devices whereby the deflection shown is proportional to the quantity being measured. 

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