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Diagram showing a method of connecting ammeter to a 300-ampere shunt.

Ammeter

Diagram showing a method of connecting ammeter to a 300-ampere shunt.

"Hot-wire instruments working on the sag principle can be used in any position if properly contructed, and are very portable." —Encyclopedia Britannica, 1910

Hot-wire Ammeter

"Hot-wire instruments working on the sag principle can be used in any position if properly contructed,…

"A much better form of electromagnetic ammeter can be constructed on a principle now extensively employed, which consists in pivoting in the strong field of a permanent magnet a small coil through which a part of the current to be measured is sent." —Encyclopedia Britannica, 1910

Shunted Movable Coil Ammeter

"A much better form of electromagnetic ammeter can be constructed on a principle now extensively employed,…

"When a current is passed through the instrument it causes one end of the movable system to tilt downwards, and the other end upwards; the sliding weight is then moved along the tray by means of a silk cord until equilibrium is again established." —Encyclopedia Britannica, 1910

Lord Kelvin's Ampere Balance

"When a current is passed through the instrument it causes one end of the movable system to tilt downwards,…