Terms and Definitions in Test and Measurement | ECE Board Exam

The field of test and measurement is crucial to engineering, science, and technology, ensuring precision and reliability. A solid understanding of its terminology is essential for professionals and learners alike.

This document offers a concise list of terms, definitions, and notes related to test and measurement, serving as a valuable reference for practitioners and students. It aims to enhance communication, problem-solving, and understanding of measurement principles.

List of Terms, Definitions, and Notes in Test and Measurement

An ammeter is an indicating instrument

As the deflection of the moving system increases, the controlling torque in an indicating instrument increases

D’Arsonval is the best type of meter movement

Wattmeter dynamometer type has uniform scale

When both deflecting and controlling torque act, the pointer of an indicating instrument comes to rest

The output voltage of a thermocouple increases with temperature

Analog instrument – an instrument in which the magnitude of the measured quantity is indicated by means of a pointer

If the pointer of an indicating instrument is in motion, damping and controlling torques oppose the deflecting torque

Electrical currents can be induced with a coil and a magnet by moving either the magnet or the coil

The fuse should never be replaced with a higher-rated unit

The pointer of an indicating instrument is generally made of aluminum

The time interval that a waveform is high (or low) is the pulse width of the signal

A Wheatstone bridge is balanced if the ratio of resistors on one side of the bridge equals the ratio of resistors on the other side

The pointer of an indicating instrument is in the final deflected position, the damping torque is zero

Deflecting force – a moving system force in analog instruments which causes the moving system to deflect from its zero position

Controlling force – a moving system force in analog instruments which ensures that the deflection of the pointer for a given value of measured quantity always has the same value

All voltmeters except electrostatic is operated by the passage of current

Disc is made of conductor and non- magnetic material in eddy current damping

The time interval between pulses is called pulse delay

An oscilloscope provides easy measurement of peak-to-peak values

Fuse is an element in electronics which serves as a protection against overload

Diode sensor provides a dc voltage of approximately 1 V at 10 mW. Diode sensors use diodes to detect radio frequency (RF) signals and produce a DC voltage. The typical power range is 0.1 nW to 10 mW; the maximum frequency is greater than 18 GHz

Hot-wire instrument has a squared scale

For time measurements, horizontal scale of the scope is used

Fluid friction damping is employed in Kelvin electrostatic voltmeter

Current range extension in moving coil instruments can be achieved by placing a low-resistance resistor in shunt with the instrument

Permanent-magnet moving coil instrument can be used in dc work only

Control grid CRT element provides for control of the number of electrons passing farther into the tube

Orthogonal nulling refers to garaging the two adjustments of an

AC bridge together in such a way that changing one adjustment changes the other in a special way, but changing the second adjustment does not change the first

When the vertical input is 0 V, the electron beam may be positioned at the vertical center of the screen

The reason why the scale of a permanent-magnet moving coil instrument is uniform is because it is spring-controlled

Thermal converters – a sensing element that provides a DC voltage less than 10mV with a typical power range of 0.1 to 100 mW

Tank circuit frequency can be measured by Grid-dip meter

Shunts are generally made of Manganin material

1 μA meter is the most sensitive

A dynamometer instrument is mainly used as a wattmeter

Dynamometer movement is the most expensive

Attraction and repulsion instrument are considered as moving iron instruments

In Wheatstone bridge, bridge balance is a condition where there is no current that flows through the load

The temperature coefficient of resistance of the shunt material is negligible

In VTVMS, zero adjust is used to balance both halves of the difference amplifier or cathode-coupled amplifier

In an oscilloscope, intensity control adjusts the brightness of the spot by changing the voltage on the control grid

Damping force – a force in analog instrument which quickly brings the moving system to rest in its final position

A small swamping resistance is connected in series with operating coil of a moving coil ammeter in order to compensate for the effects of temperature variation

The typical power range of diode sensor is 0.1 nW to 10 mW

A milliameter operates on the magnetic attraction-repulsion principles

Wheatstone bridge – a dc bridge widely used for the accurate measurement of resistance

Potentiometer bridge is a dc bridge that is very useful for making extremely accurate voltage measurements

Majority of the analog measuring instrument utilizes magnetic effect

Multimeter typically provides measurement of rms values (for a sinusoidal waveform)

Dynamometer type instrument can be used for both dc and ac works

Permanent-magnet moving coil is an instrument in which springs provide the controlling torque as well as serve to lead current into and out of the operating coil

In VTVMS, sensitivity refers to the smallest signal that can be reliably measured

The frequency of rotation in some rotating machinery can be measured by a Spectral meter

An instrument used for observing voltage and current waveforms is the oscilloscope

An electrostatic force does not act on the moving systems of analog instrument

When current through the operating coil of a moving-iron instrument is tripled the operating force becomes nine times

50 mA is the typical full-scale deflection current of a moving coil instrument

Ammeter – an instrument used for measuring the amount of current flowing in a circuit

DMM – a type of meter that gives a precise reading of voltage, current or resistance where there is the generation of samples at the input and then feeds it to a digital read-out

50 mV is the typical full-scale voltage across a moving coil voltmeter

The period of a repetitive signal is one cycle of the waveform

Cathode – an element of a CRT that releases electrons when heated indirectly by a filament

Moving-iron instrument has a squared scale

A pattern displayed by an oscilloscope which has a steady characteristic is called Lissajous

Changing the number of turns of operating coil extends the range of a moving-iron AC ammeter

Sawtooth generator is not a basic part of a CRT

For amplitude measurements, vertical scale is calibrated in either volts per centimeter (V/cm), or millivolts per centimeter (mV/cm)

Thermocouple ammeter is used to measure high-frequency currents

Electrostatic is used for measuring high direct voltage

A common technique for measuring power at high frequency is to employ a sensing element that converts the RF power to a measurable DC or low-frequency signal

The CRT provides the visual display showing the form of the signal applied as a waveform on the front screen of a cathode ray oscilloscope.

Electrostatic instruments are exclusively used as voltmeters

0.1 μW to100 μW is the typical power range of thermocouple sensors

An electric pyrometer is an instrument used to measure high-temperature

Permanent-magnet moving coil is the most sensitive

Induction watt-hour meter is the most commonly used induction-type instrument

An integrating type of instrument is the watt-hour meter

Indicating instrument is assumed to be most accurate at half of full part of the scale

On a simple ohmmeter, the 0 ohm mark is located at far right of the scale

One of the basic functions of electronic circuits is the generation and manipulation of electronic waveshapes

Cathode ray oscilloscope (CRO) provides a visual presentation of any waveform applied to the input terminals

The interval of a pulse from start to end is the period of the pulse Cathode ray tube (CRT) is considered as the “heart” of the cathode ray oscilloscope

Phosphor – a material that glows when struck by the energetic electrons in a CRT

Thermistor sensor provides a change of resistance with a typical power range of 1 μW to 10 mW and with a maximum frequency greater than 100 GHz

Most AC voltmeters have an rms scale which is valid only if the input signal being measured is a sinusoidal signal

Wheatstone bridge measures dc resistance Hay bridge is used to measure high-Q inductors (Q>10)

Maxwell bridge measures an unknown inductance in terms of known capacitance

Maxwell bridge is used for measuring medium Q coils (1Wien bridge has a series RC combination in one arm and a parallel RC combination in the adjoining arm and used as a notch filter in harmonic distortion analyzer

Sensitivity of a voltmeter is expressed in ohm/volt

The smallest change in applied stimulus that will indicate a detectable change in deflection in an indicating instrument is called resolution

Insulation material is measured by Megger

This notes combines theory and practical applications to help readers confidently navigate testing and measurement. Whether troubleshooting, designing tests, or exploring advanced concepts, this resource is essential for enhancing your expertise in the field.