ELECTRICAL (or [[Electrostatic) Machine]], a machine operating by manual or other power for transforming mechanical work into electric energy in the form of electrostatic charges of opposite sign delivered to separate conductors.
In the Nalder ohmmeter the electrostatic principle is employed.
Voltmeters may be divided into two classes, (a) electrostatic, (b) electrokinetic.
There are methods of measuring electrical power by means of electrostatic voltmeters, or of quadrant electrometers adapted for the purpose, which when so employed may be called electrostatic wattmeters.
It has in fact been found, with the very great precision of which optical experiment is capable, that all terrestrial optical phenomenareflexion, refraction, polarization linear and circular, diffraction - are entirely unaffected by the direction of the earth's motion, while the same result has recently been extended to electrostatic forces; and this is our main experimental clue.
Electrostatic voltmeters are based on the principle that when two conductors are at different potentials they attract one another with a force which varies as the square of the potential difference (P. D.) between them.
Electrostatic voltmeters are now almost entirely used for the measurement of high voltages from 2000 to 50,000 volts employed in electrotechnics.
Sumpner in 1891, an electrostatic voltmeter is employed to measure the fall of potential V 1 down any inductive circuit in which it is desired to measure the power absorption, and also the volt-drop V2 down an inductionless resistance R in series with it, and also the volt-drop V3 down the two together.
Utilizing this principle many inventors have devised forms of electrostatic voltmeter.
- Lord Kelvin's Multicellular Electrostatic Voltmeter.
Hot wire voltmeters, like electrostatic voltmeters, are suitable for use with alternating currents of any frequency as well as with continuous currents, since their indications depend upon the heating power of the current, which is proportional to the square of the current and therefore to the square of the difference of potential between the terminals.
- Round Dial Kelvin Multicellular Electrostatic Voltmeter, 5-in.
Like the corresponding ammeters, they have the great advantage that the scales are equidivisional and that there is no dead part in the scale, whereas both the electrostatic and electrothermal voltmeters, above described, labour under the disadvantage that the scale divisions are not equal but increase with rise of voltages, hence there is generally a portion of the scale near the zero point where the divisions are so close as to be useless for reading purposes and are therefore omitted.
This measurement is applicable to the measurement of high potentials, either alternating or continuous, provided that in the case of alternating currents the high resistance employed is wound non-inductively and an electrostatic voltmeter is used.
It is always an advantage, if possible, to employ an electrostatic voltmeter for measuring potential difference if it is necessary to keep the voltmeter permanently connected to the two points.
(iii.) The instrument should have no temperature correction; this is a good quality of electrostatic instruments, but in all voltmeters of the electrokinetic type which are wound with copper wire an increase of one degree centigrade in the average temperature of that wire alters the resistance by 0.4%, and therefore to the same extent alters the correctness of the indications.
In other types of electrostatic instruments the movable system rotates round a horizontal axis or rests upon knife edges like a scale beam; in others again the movable system is suspended by a wire.
Electrostatic instruments, however, take up no power and hence cost nothing for maintenance other than wear and tear of the instrument.
The unit of electrostatic capacity is therefore that of a sphere of I cm.
In this case a highresistance wire is connected between the points of which the potential difference is required, and from some known fraction of this resistance wires are brought to an electrostatic voltmeter, or to a movable coil electromagnetic voltmeter, according as the voltage to be measured is alternating or continuous.
The separation also sets up electrostatic forces, which increase until they are strong enough to drag the slower moving ions along faster, and to retard the naturally faster ions till they travel at the same rate.
That's true but the electrostatic attraction is something we're just beginning to understand.
Electrostatic fields come from a voltage gradient and can exist when charge carriers are stationary.
The unit to which they are ordinarily referred is I electrostatic unit of electricity per cubic metre of air.
Taking i volt equal 1/300 of an electrostatic unit, we find M =0.000265.
resistance and its electrostatic capacity are then measured.
What's this negative-positive business and electrostatic field?
This gives a convection current of 2.7 X108 electrostatic units, or about 1/27 of the conduction current.
Up to 1895 or 1896 the suggestions for wireless telegraphy which had been publicly announced or tried can thus be classified under three or four divisions, based respectively upon electrical conduction through the soil or sea, magnetic induction through space, combinations of the two foregoing, and lastly, electrostatic induction.
Electrostatic machines are of two kinds: (I) Frictional, and (2) Influence machines.
These operate by electrostatic induction and convert mechanical work into electrostatic energy by the aid of a small initial charge which is continually being replenished or reinforced.
If this series of operations be made to depend upon the continuous rotation of a winch or handle, the arrangement constitutes an electrostatic influenceenachine.
Holtz constructed and described a large number of influence machines which were for a long time considered the most advanced development of this type of electrostatic machine.
It was an electrostatic and electromagnetic machine combined, driven by an electric current and producing in turn electrostatic charges of electricity.
His most important discovery, however, was that of electrostatic induction, the fact that one electrified body can produce charges of electricity upon another insulated body, and that when this last is touched it is left electrified with a charge of opposite sign to that of the inducing charge (Phil.
A contemporary of Canton and co-discoverer with him of the facts of electrostatic induction was the Swede, Johann Karl Wilcke (1732-1796), then resident in Germany, who in 1762 published an account of experiments in which a metal plate held above the upper surface of a glass table was subjected to the action of a charge on an electrified metal plate held below the glass (Kon.
Hence his measurements are all directly comparable with modern electrostatic measurements in which the unit of capacity is that of a sphere r centimetre in radius.
Similarly he came to see an electrified body as a centre of a system of lines of electrostatic force.
The 11th series (1837) deals with electrostatic induction and the statement of the important fact of the specific inductive capacity of insulators or dielectrics.
In 1846 Weber announced his famous hypothesis concerning the connexion of electrostatic and electrodynamic phenomena.
Maxwell never committed himself to a precise definition of the physical nature of electric displacement, but considered it as defining that which Faraday had called the polarization in the insulator, or, what is equivalent, the number of lines of electrostatic force passing normally through a unit of area in the dielectric. A second fundamental conception of Maxwell was that the electric displacement whilst it is changing is in effect an electric current, and creates, therefore, magnetic force.
The two systems of measurement were called respectively the electrostatic and the electromagnetic systems (see Physical Units).
Maxwell suggested new methods for the determination of this ratio of the electrostatic to the electromagnetic units, and by experiments of great ingenuity was able to show that this ratio, which is also that of the velocity of the propagation of an electromagnetic impulse through space, is identical with that of light.
After he had educated himself by the study of the phenomena of lines of magnetic force in his discoveries on electromagnetic induction, he applied the same conception to electrostatic phenomena, and thus created the notion of lines of electrostatic force and of the important function of the dielectric or non-conductor in sustaining them.
Each electron is a point-charge of negative electricity equal to 3.9 X Io 1 ° of an electrostatic unit or to.
An electrometer is an instrument for measuring difference of potential, which operates by means of electrostatic force and gives the measurement either in arbitrary or in absolute units.
or electrostatic units.
electrostatic capacity is correspondingly small.
The upper end of the quartz fibre is rotated by a torsion head, and a metal cover serves to screen the instrument from stray electrostatic fields.
He studied the reflection and polarization of radiant heat, the magnetism of rocks, electrostatic induction, daguerrotypy, &c.
The cathode terminal is connected to the negative pole of an electrostatic machine, such as a Wimshurst or Voss machine, giving a steady pressure.
A typical barrow, in effect, is more like an ' orgone accumulator ' than an electrostatic accumulator.
The effect of lower sulfur coal blends on the performance of electrostatic precipitators and fabric filters is also covered.
electrostatic repulsion of the protons.
electrostatic discharge The rapid transfer of a voltage potential into a circuit or component.
electrostatic charging of the sail must also be considered.
electrostatic interactions; they are all computed.
electrostatic air cleaners remove these pollutants, leaving a healthier environment for everyone.
For particles in aqueous solution the interparticle forces are predominantly electrostatic in origin.
There are also electrostatic fields, e.g. between battery terminals.
electrostatic in origin, reflecting the polar nature of the participating groups.
He solved the problem by combining an electrostatic generator with an electric motor: the Froment mouse-mill motor.
Rupert signaled to Mr.Matthews, to instruct his men to begin turning the huge frictional electrostatic generators once again.
Topics include: basic electrostatics, electrostatic induction, Coulomb's Law, electric field strength, and electric potential.
High efficiency electrostatic precipitators or fabric filters can reduce particulate emissions to low concentrations.
orgone accumulator ' than an electrostatic accumulator.
The reason for this is the electrostatic repulsion of the protons.
Using electrostatic deflexion to divert and collect cells with one or more fluorescent labels enables defined subpopulations to be sorted.
A probe connects an electrostatic voltmeter to the hand.
The charge on the earth itself has its surface density given by v = - (I/47r) X125 volts per metre, =0.000331 in electrostatic units.
From this we deduce for the charge p per cubic centimetre (I/41r)Xio-5 (volt/cm 2), or 2.7 X 101 electrostatic units.
6 X 300), or 73 XI 08 in electrostatic measure, otherwise 2.4X1016 amperes per sq.
As to the convection current, Gerdien supposes-as in § 25-p =2-7 X 10Ã‚° electrostatic units, and on fine days puts the average velocity of rising air currents at 10 cm.
The great advantage of this air insulation is that the electrostatic capacity of the wires is low (about one-third of that which would be obtained with gutta-percha insulation), which is of the utmost importance for high-speed working or for longdistance telephonic communication.
Each conductor has a resistance (at 60Ã‚° F.) of 5.74 ohms per statute mile, and an average electrostatic capacity per mile between adjacent wires of o 06 microfarad, or between wire and earth of o I microfarad; the insulation resistance of each wire is about 5000 megohms per mile.
Before the classical researches of Hertz in 1886 and 1887, many observers had noticed curious effects due to electric sparks produced at a distance which were commonly ascribed to ordinary electrostatic or electro-magnetic induction.
The dimensions of a capacity in electrostatic measure is a length (see Physical Units).
Thus the capacity of a sphere in electrostatic units (E.S.U.) is the same as the number denoting its radius in centimetres.
Addenbrooke, "The Electrostatic Wattmeter and its Calibration and Adaptation for Polyphase Measurements," Electrician (1903), 51, 811; W.
One large class of electrostatic voltmeters consists of a fixed metal plate or plates and a movable plate or plates, the two sets of plates forming a condenser (see Leyden Jar).
One much-used electrostatic voltmeter of this type is the Kelvin multicellular vertical pattern voltmeter (fig.
The jar has a certain capacity C which is best expressed in microfarads or electrostatic units (see Electrostatics), and is determined by the surface of the tin foil and thickness and quality of the glass.
Each electron is a point-charge of negative electricity equal to 3.9 X Io 1 Ã‚° of an electrostatic unit or to.
ELECTROMETER, an instrument for measuring difference of potential, which operates by means of electrostatic force and gives the measurement either in arbitrary or in absolute units (see Physical Units).
The collar is designed to deliver a small electrostatic shock whenever your dog barks.
You have the option of setting the receiver to emit either a tone or an electrostatic stimulation when you push the button.
The electrostatic charge is comparable to the static poke you might feel if you walked on a carpet and then touched a metal object.
Ionic purifiers do not have an internal fan that pushes the air through the filters; instead, they rely on an electrostatic system.
An electrostatic collector cell then captures and destroys the particles.
Three of the best air purifiers/ionizers include the Oreck XLTower Electrostatic Air Purifier, the Sharper Image Ionic Breeze, and the Ionic Pro Electronic Air Purifier.
True to his word, his Oreck XL tower electrostatic air purifier is one of the top air purifiers on the market.
It features electrostatic plates which unlike the Oreck XL, can be cleaned with a damp cloth.
These units all operate without a fan and use electrostatic technology to attract particles.
Electrostatic voltmeters are also liable to have their indications disturbed by electrification of the glass cover of the instrument; this can be avoided by varnishing the glass with a semi-conducting varnish so as to prevent the location of electrostatic charges on the glass.
For simplicity, he assumes I + and I_ each equal 0.25 X106 electrostatic units.
Within a few years several methods had been proposed by different inventors, but none was at first very successful, not from any fault in the principle, but because the effect of electrostatic capacity of the line was left out of account in the early arrangements.
By this method of transmission the battery is always to the line for the same interval of time, and alternately with opposite poles, so that the effect of electrostatic induction is reduced to a minimum.
Dolbear, 2 the effects were produced by electrostatic instead of electromagnetic forces, as in con- the Bell telephone.
Moreover, his association with glass manufacture led him to study the refractive indices of different kinds of glass; he further undertook abstruse researches on electrostatic capacity, the phenomena of the residual charge, and other problems arising out of Clerk Maxwell's electro-magnetic theory.
If a small conducting body is charged with Q electrostatic units of electricity, and placed in any electric field at a point where the electric force has a value E, it will be subject to a mechanical force equal to QE dynes, tending to move it in the direction of the resultant electric force.
The above method is especially useful for the determinations of very small capacities of the order of Ioo electrostatic units or so and upwards.
For working long submarine cables the apparatus ordinarily employed on land lines cannot be used, as the retarding effect of the electrostatic capacity of the cable is so marked that signals fail to be recorded except at a very slow speed of working.
field created round one circuit to induce, when varied, a secondary current in another circuit, there have been certain attempts to utilize what may best be described as electrostatic induction.
Before the spark happens lines of electrostatic force stretch from one to the other in curved lines.
The electrostatic capacity of a cable of this type is low, and its dimensions are small, the external diameter of a cable containing 1600 ten-lb conductors being only 24 in.
30 be numerically the same as the ratio of the electromagnetic and electrostatic units.
This process will go on until the simultaneous separation of electric charges produces an electrostatic force strong enough to prevent further separation of ions.
1 See Lord Kelvin, " Report on Electrometers and Electrostatic Measurements," Brit.
The electrified ebonite is said to act by " electrostatic induction " on the tray, and creates on it two induced charges, one of positive and the other of negative electricity.
In the next place we must notice that electrification is a measurable magnitude and in electrostatics is estimated in terms of a unit called the electrostatic unit of electric quantity.
A very small sphere is said then to possess a charge of one electrostatic unit of quantity, when it repels another similar and similarly electrified body with a force of one dyne, the centres being at a distance of one centimetre, provided that the spheres are in vacuo or immersed in some insulator, the dielectric constant of which is' taken as unity.
If the two small conducting spheres are placed with centres at a distance d centimetres, and immersed in an insulator of dielectric constant K, and carry charges of Q and Q' electrostatic units respectively, measured as above described, then the mechanical force between them is equal to QQ'/Kd 2 dynes.
In the same manner, if an electrified body carries a positive charge Q electrostatic units and is placed in an electric field at a place where the electric force or electromotive intensity has a value E units, it is urged in the direction of the electric force with a mechanical force equal to QE dynes.
Our work concerns electrostatic forces; force fields that surround us everywhere.
Returning to the case of the charged body with the space around it cut up into electric cells by the tubes of force and shells of potential, it is obvious that the number of these cells is represented by the product QV, where Q is the charge and V the potential of the body in electrostatic units.
The quantity of electricity which must be given to the sphere to raise it to unit potential is therefore R electrostatic units.
He supposes the field near the earth to be ioo volts per metre, or 1/300 electrostatic units.
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