By using over five kilometers of copper wire coiled nearly 24,000 times around a magnet, he constructed a galvanometer capable of measuring electrical potential differences on a scale of millivolts.
In each test the operator measured the skin impedance at this point as indicated in arbitrary units on the galvanometer while the patient held the hand electrode to complete the electrical circuit.
The galvanometer rotates mirrors to change the image that is directed from the workpiece to the camera.
The testing is done by passing a weak current through the circuit in which a small galvanometer is included and if the needle of the instrument moves when a connexion is made the circuit is in order.
In 1902, a Dutch physiologist published the first ECG recorded with his 270-kg machine, the string galvanometer , for which he was awarded a Nobel Prize.
This in turn gives the galvanometer a greater readability, and by keeping the mass and inertia of the actual moving element low, a greater sensitivity.
For mapping the field distribution in the BR film and BGO crystal, 532 nm light is deflected by a gold-plated mirror servoactuated by a galvanometer .
Below is a conventional galvanometer with magnetic needle; above are two concentric coils of fine wire and a needle suspended from six limbs between the two coils.
A somewhat similar galvanometer is listed in the 1887 Queen catalogue of electrical testing apparatus at $156.00.
Polygonal scanners compete as output devices with galvanometers , acousto-optic deflectors, holographic scanners, and micromirror devices.