# electrometer

## Definitions

• WordNet 3.6
• n electrometer meter to measure electrostatic voltage differences; draws no current from the source
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Webster's Revised Unabridged Dictionary
• n Electrometer (Physics) An instrument for measuring the quantity or intensity of electricity; also, sometimes, and less properly, applied to an instrument which indicates the presence of electricity (usually called an electroscope).
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Century Dictionary and Cyclopedia
• n electrometer An instrument for measuring difference of electrostatic potential between two conductors. See potential. There are many forms. The absolute electrometer (also called balance electrometer) of Sir William Thomson consists essentially of two parallel circular plates attracting each other, the central portion of one of them, the upper, suspended from one arm of a balance or by means of light steel springs, the other being movable to a greater or less distance from the first by means of a micrometer screw. The upper disk is always brought to a fixed position (which can be very accurately determined) by means of the attraction of the lower, the amount of attraction being regulated by the distance between the two plates. It is thus seen that the electric force is actually weighed, and formulas are given by means of which the difference of potentials is deducible in absolute measure, the areas of the plates and the distance between them being known. The quadrant electrometer of Sir William Thomson consists of four quadrant-shaped pieces of metal, sometimes segments of a flat cylindrical box, the alternate pairs being connected by a wire; above or within this, if the cylindrical form is used, a flat needle of aluminium is hung by a delicate wire. The needle is kept in a constant electrical condition by connection usually with a Leyden jar placed above or below, and if the two pairs of quadrants are dissimilarly electrified—that is, are in a state of different potential, as by connecting them respectively with the poles of a voltaic cell—the needle is dettected from its position of rest, and the amount of this deffection, as measured by the motion of a spot of light reflected from a small mirror attached to it, gives a means of calculating the difference of potential of the bodies under experiment. In another method of using the quadrant electrometer the pairs of quadrants are kept at a constant difference of potential, while that of the needle varies. Arranged in this manner, it is much used in the investigation of atmospheric electricity. Lippmann and Dewar have devised very delicate capillary electrometers, based on the alternation of the force of capillarity by electric action. See electrocapillary.
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Chambers's Twentieth Century Dictionary
• Electrometer an instrument for measuring the quantity of electricity
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## Etymology

Webster's Revised Unabridged Dictionary
Electro-, + -meter,: cf. F. électromètre,

## Usage

### In literature:

It worked very well on the occasion of our departure from the earth, and gave, without the condenser, one degree to the electrometer.
"Wonderful Balloon Ascents" by Fulgence Marion
Finally, before each screen there was a pith-ball electrometer.
"Scientific American Supplement, No. 384, May 12, 1883" by Various
The quantity of oxygen and hydrogen collected in the volta-electrometer = 3.85 cubic inches.
"Experimental Researches in Electricity, Volume 1" by Michael Faraday
The observations were made by means of an electrometer.
"Scientific American Supplement, No. 633, February 18, 1888" by Various
Its appearance did not affect the electrometer, nor could we perceive the compass to be disturbed.
"Narrative of a Journey to the Shores of the Polar Sea, in the Years 1819-20-21-22, Volume 1" by John Franklin
Among Sir William's other inventions we may specially mention an electrometer, which has now assumed a very complete form.
"Western Worthies" by J. Stephen Jeans
Cholera and the electrometer, 319.
"Notes and Queries, Index of Volume 5, January-June, 1852" by Various
The amount of the charge which they carry may be measured by the electrometer.
"A History of Science, Volume 5(of 5)" by Henry Smith Williams
By electrical methods, using electroscopes, quadrant electrometers, etc.
"A Brief Account of Radio-activity" by Francis Preston Venable
The basis is the capillary electrometer.
"The Social Gangster" by Arthur B. Reeve
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### In science:

See Supplementary Section SI D for explanation of the frequencies where the current is not quantized. A systematic offset of 40 fA due to the uncalibrated electrometer has been subtracted from the raw data.
Gigahertz quantized charge pumping in graphene quantum dots
The single electron current is small, but can be measured using sensitive electrometers.
A Self Assembled Nanoelectronic Quantum Computer Based on the Rashba Effect in Quantum Dots
If the qubit was in |1i, the atom will ﬂuoresce, a stream of electrons will ﬂow in a ne arby photomultiplier tube, and a signal will appear on the display of an electrometer.
Experimental Quantum Computation with Nuclear Spins in Liquid Solution
If the atom was in |0i, the electrometer will show no signal.
Experimental Quantum Computation with Nuclear Spins in Liquid Solution
Locally applied electric ﬁelds would produce one-qubit gates and read-out would be done by selectively releasing excited electrons from the surface, and absorbing them in an electrometer placed above the surface.
Experimental Quantum Computation with Nuclear Spins in Liquid Solution
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