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A solenoid voltmeter is a specific type of voltmeter used by electricians in the testing of electrical power circuits.〔Michael E. Brumbach ''Industrial electricity'' 7th ed. , Cengage Learning, 2004 ISBN 1-4018-4301-8, pp. 45-46〕 Wiggy is the registered trademark for a common solenoid voltmeter used in North America derived from a device patented in 1918 by George P. Wigginton.〔David E. Shapiro "Your Old Wiring", McGraw-Hill Professional, 2001 ISBN 0-07-135701-7 page 22〕 ==Operation== Rather than using a D'Arsonval movement or digital electronics, the solenoid voltmeter simply uses a spring-loaded solenoid carrying a pointer (it might also be described as a form of moving iron meter). Greater voltage creates more magnetism pulling the solenoid's core in further against the spring loading, moving the pointer. A short scale converts the pointer's movement into the voltage reading.〔Kenneth G. Mastrullo, Ray A. Jones ''The Electrical Safety Program Book'', Jones & Bartlett Learning, 2003 ISBN 0-7637-4368-2 page 70〕 Solenoid voltmeters usually have a scale on each side of the pointer; one is calibrated for alternating current and one is calibrated for direct current. Only one "range" is provided and it usually extends from zero to about 600 volts. A small permanent magnet rotor is usually mounted at the top of the meter. For DC, this magnet flips one way or the other, indicating by the revealed color (red or black) which lead of the voltmeter (the red or the black lead) is positive. For AC, the rotor simply vibrates, indicating that the meter is connected to an AC circuit. Another form of tester uses a miniature neon lamp; the negative electrode glows, indicating polarity on DC circuits, or both electrodes glow, indicating AC. Models made by some manufacturers include continuity test lights, which are energized by a battery within the tester. This is particularly advantageous when testing, for example, fuses in live circuits, since no switching is required to change from continuity mode to voltage detecting mode. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Solenoid voltmeter」の詳細全文を読む スポンサード リンク
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