Voltmeter Sentence Examples
In the same manner the potentiometer may be used to calibrate a voltmeter by the aid of a divided resistance of known value.
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.
Utilizing this principle many inventors have devised forms of electrostatic voltmeter.
Numerous forms of hot-wire or thermal voltmeter have been devised.
A high-resistance electrodynamometer may be employed as a voltmeter.
Consider, for instance, a hot-wire instrument, such as a Cardew's voltmeter.
One of the best known of these is Lord Kelvin's multicellular voltmeter.
For Volta's electrical work, and his place in the history of discovery (see Electricity; also Voltmeter).
Three springs press against the cylinder and make contact for a short time during each revolution, so that a condenser is charged by the circuit at an assigned instant during the alternating current phase, and then subsequently connected to a voltmeter.
This process, so to speak, samples or tests the varying electromotive force of the alternating current at one particular instant during the phase and measures it on a voltmeter.Advertisement
A probe connects an electrostatic voltmeter to the hand.
If you have a voltmeter or DVM select the 200 volt range and connect it across the output.
Replacing the high resistance voltmeter with a bulb in the above cells allows a current to flow.
If the voltmeter reading is still zero volts, an improper connection still exists in the equipment.
Then, once you have ensured that the battery exhaust tube is open and serviceable, firmly replace the battery caps and test the battery with either a hydrometer or voltmeter.Advertisement
Check the fuse by carefully removing and testing it with your Voltmeter.
The setting for the Voltmeter should be set to "RX100".
Hence devices for detecting the oscillations in the antenna are merely very sensitive forms of ammeter and voltmeter.
A voltmeter isan instrument for measuring difference of electric potential in terms of the unit called a volt.
A voltmeter is therefore one form of electrometer, but the term is generally employed to describe the instrument which indicates on a scale, not merely in arbitrary units but directly in volts, the potential difference of its terminals.Advertisement
In that known as the Cardew voltmeter, a fine platinum-silver wire, having a resistance of about 300 ohms, is stretched in a tube or upon a frame contained in a tube.
In the Hartmann and Braun form of hot-wire voltmeter, the fine wire is fixed between two supports, and the expansion produced when a current is passed through it causes the wire to sag down, the sag being multiplied by a gear and made to move an indicating needle over a scale.
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.
Any form of electrokinetic voltmeter which involves the passage of a current through the wire necessitates the expenditure of energy to maintain this current and therefore involves cost of production.Advertisement
Since there are 8760 hours in a year, if such an instrument were connected continuously to the circuit it would take up energy equal to 263,000 watt-hours, or 260 Board of Trade units per annum, If the cost of production of this energy was only one penny per unit, the working expenses of keeping such a voltmeter in connexion with a circuit would therefore be more than £i per annum, representing a capitalized value of, say, £io.
The principles of telegraphy (land, submarine and wireless) and of telephony are discussed in the articles Telegraph and Telephone, and various electrical instruments are treated in separate articles such as Amperemeter; Electrometer; Galvanometer; Voltmeter; Wheatstone'S Bridge; Potentiometer; Meter, Electric; Electrophorus; Leyden Jar; &C.
The voltmeter needle may then be made to record its variations graphically on a drum covered with paper and so to delineate the wave form of the current.
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.
This contact may be made to close the circuit of a suitable voltmeter, or to charge a condenser in connexion with it, and the reading of the voltmeter will therefore not be the average or effective voltage of the alternator, but the instantaneous value of the electromotive force corresponding to that instant during the phase, determined by the position of the rotating contact slip with reference to the poles of the alternator.