LE1 Flashcards by Czar Michael Cuan

D’Arsonval meter movement is also called as …

PMMC

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What is the accuracy of D’Arsonval meter?

2%-5%

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What are the types of analog meter?

Plunger Style moving vane, Radial vane, Concentric vane

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It is the human error of reading the analog meter from an angle.

Parallax Effect

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What do you call the resistor that is added to vary the range of the ammeter?

Shunt resistor

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What do you call the resistor that is added to vary the range of the voltmeter?

Multiplier resistance

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When a voltmeter is in parallel with the circuit component being measured, the total resistance of the circuit _______ and the voltage across the component also ______. This error is called the ______.

decreases ; decreases; voltmeter loading error

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When the ammeter is inserted in series in the circuit, the total resistance of the circuit _______ and the current in the circuit ______. This error is called the ______.

increases ; decreases ; ammeter insertion error

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Enumerate different Wheatstone bridge types.

Maxwell, Hay, Schering, Wien

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He never claimed to be the inventor of the bridge circuit. However, he invented many uses for it.

Sir Charles Wheatstone

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It is an electrical device used to measure the CHANGE in its resistance

Wheatstone bridge

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The Wheatstone bridge gets more sensitive when it is supplied with lower voltages. True or False?

False. The Wheatstone bridge gets more sensitive when it is supplied with HIGHER voltages.

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Null detector for AC bridge can be made using headphones. True or False?

True

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When the null detector for AC bridge is balanced, what do you hear in the headphones? What if the AC bridge is unbalanced?

nothing ; clicking sounds

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Hay bridge is an AC bridge that is used to determine unkown _____.

inductance

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Maxwell bridge is an AC bridge that is used to determine unkown _____.

inductance and resistance

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Schering bridge is an AC bridge that is used to determine unkown _____.

capacitance and resistance

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Wien bridge is an AC bridge that is used to determine unkown _____.

capacitance

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What are the 3 functions of instruments and measurement systems?

indicating, recording, and controlling function

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What are the 3 applications of measurement systems?

monitoring, and control of process and operation, and experimental engineering analysis

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What are the elements of a generalized measuring system?

primary sensing element, secondary sensing element, data presentation element

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State the 5 stages in elements of a generalized measuring system.

primary sensing element - variable conversion element - variable manipulation element - data transmission element - data presentation element

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What can be found in the primary sensing element?

transducers

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To measure AC in EDM, a _____ is used to produce unidirectional torque.

rectifier

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It is the production of voltage across a conductor when it is exposed to a varying magnetic field

Electromagnetic induction

When one circuit induces current flow in a second nearby circuit, it is known as \_\_\_\_\_.

Mutual inductance

The _______ is ideal for measuring the large magnetic fields associated with AlNiCo magnets, coils and beta spectrometers.

Tesla meter

A magnetometer for the measurement of the magnetic induction B or magnetic field intensity.

Tesla meter

The unit of magnetic induction in the International System of Units.

Tesla

A region around a magnetic material or a moving electric charge within which the force of magnetism acts.

magnetic field

A measure of the quantity of magnetism, being the total number of magnetic lines of force passing through a specified area in a magnetic field.

magnetic flux

Unit of magnetic flux

Weber

The amount of flux per unit area of the field, which is perpendicular to the direction of flux

Flux density

Unit of flux density

Tesla

The most common teslameters are based on the _____ principle and consist of an _______ and an \_\_\_\_\_\_\_\_\_\_\_.

induction , inductance coil, electrical measuring instrument.

When a change occurs in the magnetic flux linkage between the inductance coil and the magnetic field whose induction is to be determined, an _________ , which is measured by the instrument, is generated in the coil.

electromotive force

In constant magnetic fields the flux linkage changes as a result of \_\_\_\_\_\_, \_\_\_\_\_\_, or _______ of the inductance coil

linear displacement, rotation, vibration

In ______ magnetic fields, the change in flux linkage results from a change in the magnitude and direction of the field.

variable

\_\_\_\_\_\_\_ are used as the measuring instruments in the case of constant fields

Fluxmeters

Voltmeters, oscillographs, and other such devices are used in the case of _____ fields.

variable

Give the Tesla meter applications

* Assessment of magnetic materials. * Analysis of magnetic circuits and components •Measurement of residual magnetism * Measure stray and leakage fields * Measurement of absolute, and •differential fields * Testing, sorting, classifying magnets * DC and AC motor testing * Relay and solenoid test * Loudspeaker test ranges.

The \_\_\_\_\_\_, is the cgs unit of measurement of a magnetic field B, which is also known as the "magnetic flux density" or the "magnetic induction".

Gauss

One gauss is defined as one \_\_\_\_\_\_\_

maxwell per square centimeter.

One gauss equals ______ Tesla

1×10−4

The gauss is the unit of magnetic flux density B, while the ___________ is the unit of magnetizing field H.

oersted

One tesla is equal to \_\_\_\_\_\_\_gauss

1x10^4

The unit of electric field in the MKS system of units is \_\_\_\_\_\_\_\_\_

newtons per coulomb (N/C)

The magnetic field (in teslas) can be written as \_\_\_\_\_\_\_\_

N/(C·m/s)

Whether a static electromagnetic field is seen as purely magnetic, or purely electric, or some combination of these, is dependent upon one's ____________ (that is: one's velocity relative to the field).

reference frame

In ferromagnets, the movement creating the magnetic field is the \_\_\_\_\_\_\_\_\_\_\_\_

electron spin

In a current-carrying wire the movement is due to ____________ moving through the wire

electrons

TRUE OR FALSE: The direction of the magnetic field B at any point is the same as the direction indicated by this compass.

TRUE

TRUE OR FALSE: Field B is strong where lines are dense and weak where lines are sparse.

TRUE

TRUE OR FALSE: Flux lines are in the direction of force

FALSE (flux is perpendicular to the direction of force)

A greater magnetic force F will cause an \_\_\_\_\_\_\_(increase or decrease) in velocity v, an\_\_\_\_\_\_\_(increase or decrease) in charge q, and a _______ (smaller or larger) magnetic field B.

increase, increase, larger \*F is directly proportional to q, V, and B\*

With a flat right hand, point thumb in direction of ________ , fingers in direction of \_\_\_\_\_\_\_\_. The flat hand pushes in the direction of \_\_\_\_\_

velocity, magnetic field, force

TRUE OR FALSE: The force is greatest when the velocity v is perpendicular to the B field.

TRUE

TRUE OR FALSE: The deflection decreases to zero for parallel motion.

TRUE

A magnetic field intensity of one tesla (T) exists in a region of space where a charge of ________ moving at ____ m/s perpendicular to the B-field will experience a force of _____ newton (N).

one Coulumb, one, one

Forces on negative charges are opposite to those on positive charges. The force on the negative charge requires a __________ rule to show downward force F.

left-hand

The direction of forces on a charge moving in an electric field can be determined by the right-hand rule for __________ charges and by the left-hand rule for ________ charges.

positive, negative

A change in flux of ______ weber per second will induce an electromotive force of _______ volt.

one ,one

The ______ may be defined in terms of Faraday's law, which relates a changing magnetic flux through a loop to the electric field around the loop.

weber

1 Weber = ____ Maxwell

10^8

The magnetic interaction is described in terms of a \_\_\_\_\_\_\_.

vector field

The ________ is the net number of field lines passing through that surface.

magnetic flux

\_\_\_\_\_\_\_\_\_\_\_ law states that a moving charge q, when acted upon by a magnetic induction field →B, will experience a force → F that is at right angles to the field vector and the velocity vector v of the charge.

Lorentz' force law

True or FALSE The Hall effect device consists of a flat, thin rectangular conductor or semiconductor with two pairs of electrodes at right angles to one another

TRUE

Hall-effect gauss meters are most effective for measuring flux densities ranging from ________ μT to _______ T .

50 μT to 30 T.

A ________ is an electronic device that provides a digital readout of the magnetic field strength in gauss or tesla units

Hall-effect meter

Hall effect gauss meter's probes are available with either ______ or __________ sensing elements.

tangential/transverse, axial

Determine the type of bridge circuit shown