Electrical Measuring Instruments

Electrical Measuring Instruments
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Electrical Measuring Instruments

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Electrical Measuring Instruments
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calibration and the need of calibration for measuring instruments.

Description : calibration and the need of calibration for measuring instruments.

Last Answer : Calibration - It is a process of estimating the value of a quantity by comparing that quantity with a standard quantity.    Need of calibration: - Calibration defines the accuracy and ... aim of calibration is to minimize any measurement uncertainty by ensuring the accuracy of test equipment.

Explain the essential toques in analog type measuring instruments.

Description : Explain the essential toques in analog type measuring instruments.

Last Answer : List of torques in analog instruments:  1. Deflecting torque  2. Controlling / Restraining torque.  3. Damping torque.  1. Deflecting torque: To create deflection proportional to ... the speed higher will be the damping torque bringing the pointer to the equilibrium position quickly. 

State two purposes of calibration of measuring instruments.

Description : State two purposes of calibration of measuring instruments.

Last Answer : Purposes of calibration of measuring instruments: - The purpose of calibration is to ensure that readings of an instrument are consistent with other instruments. It is also important in determining the ... will need to be calibrated periodically to make sure it can function properly and safely. 

List three types of errors in measuring instruments. Give reasons of occurring for any one of them.

Description : List three types of errors in measuring instruments. Give reasons of occurring for any one of them.

Last Answer : Types of errors in measuring instruments:  A) Gross error: These are due to mistakes on the part of person using the instrument.  B) Systematic Error: i) Instrumental Error: These ... multiplying factor.  C) Random error: These persist even after gross and systematic errors are removed.

Define following terms related to measuring instruments: i) Sensitivity ii) Selectivity.

Description : Define following terms related to measuring instruments: i) Sensitivity ii) Selectivity.

Last Answer : i) Sensitivity: It is the ratio of the change in output signal to the change in input signal of quantity being measured.  ii) Selectivity: It is the term to describe fulfillment of the requirements of measurement by an instrument to be suitable for use in a given situation. 

List out any four effects of electric current used in measuring instruments & write name of meter working on it.

Description : List out any four effects of electric current used in measuring instruments & write name of meter working on it.

Last Answer : Effects of Electric Current used in measuring instruments:  1. Magnetic Effect: PMMC and Moving Iron type Ammeters, voltmeter and Dynamometer type wattmeters etc.  2. Electromagnetic induction ... . Electrostatic effect: Voltmeters.  5. Hall Effect: Flux meter, Poynting vector wattmeter.

Describe systematic errors in measuring instruments.

Description : Describe systematic errors in measuring instruments. 

Last Answer : Systematic errors: -  ➢ Instrumental Error: These errors are caused due to the mechanical structure of measuring instrument.  a) Inherent shortcomings of instruments: Instrument may read ... or electrostatic fields.  ➢ Observational Error: Parallax errors, incorrect multiplying factor. 

List any four effects employed in measuring instruments.

Description : List any four effects employed in measuring instruments.

Last Answer : Effects Employed in Measuring Instruments: 1. Magnetic Effect 2. Electromagnetic induction 3. Heating effect 4. Electrostatic effect 5. Hall Effect 

What are the test and measuring instrument required in an Electrical depots?

Description : What are the test and measuring instrument required in an Electrical depots?

Last Answer : Ans. Following are the test and measuring instruments required in an Electrical depots. a. Test lamp b. Line Tester c. Continuity tester d. Volt meter e. Ammeter f. Earth megger g. Megger h. Lux meter i. Power analyzer j. Infrared thermometer

State the function of controlling torque in electrical measuring instrument.

Description : State the function of controlling torque in electrical measuring instrument.

Last Answer : Function of controlling torque  1. The function is to opposes the deflection force and increases with the increase in the deflection of the moving system, to limit its movement. 2. and brought ... set a position where the two opposing forces i.e. deflection and controlling forces are equal. 

Define: (i) Resolution, (ii) Calibration, with reference to electrical measuring systems.

Description : Define: (i) Resolution, (ii) Calibration, with reference to electrical measuring systems.

Last Answer : Resolution The smallest increment in input (the quantity being measured) which can be detected with certainty by an instrument is called its resolution or discrimination.  OR It is ... the measuring instrument with standard instrument to find out the error in the instrument under test.

Write a short note on Measuring Flask

Description : Write a short note on Measuring Flask

Last Answer : Measuring Flask : Flask is laboratory vessels (container). The flask is made of plastic or glass. They are of different sizes and shapes. In school laboratory, 50ml, 100ml, 250ml, 500ml & 1000ml ... of different sizes and shapes. In laboratory 10ml to 25 ml pipette of glass or plastic are used.

Describe spring control method of producing controlling torque in measuring instrument. Write any two properties required for spring material.

Description : Describe spring control method of producing controlling torque in measuring instrument. Write any two properties required for spring material.

Last Answer : A)Spring control method: As shown in the figure, the inner ends of the both springs are attahced to the spindle, while outer end of upper spring is attached to the lever and outer ... of spring material: 1.Non Magnetic material 2.Low specific resistance 3.Low temperature coefficient of resistance

Name the different torque and their function in measuring instrument.

Description : Name the different torque and their function in measuring instrument.

Last Answer : List of torques in analog instruments:  1. Deflecting torque  2. Controlling / restraining torque.  3. Damping torque.  1. Deflecting torque:  - To create deflection of pointer ... .  - Bring the pointer to standstill quickly.  - To minimize oscillations about final position. 

Give the classification of the errors used in measuring instrument & state the reason for their occurrence.

Description : Give the classification of the errors used in measuring instrument & state the reason for their occurrence.

Last Answer : Types of errors in measuring instruments:  A) Gross error: These are due to mistakes on the part of person using the instrument.  B) Systematic Error:  i) Instrumental Error: These ... multiplying factor.  C) Random error: These persist even after gross and systematic errors are removed. 

What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.

Description : What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.

Last Answer : 1. Error due to stray magnetic fields-   Main magnetic field gets disturbed by external magnetic fields known as stray magnetic fields.  2. Compensation technique   To avoid this error, ... resistance alloy having a negligible resistance temp coefficient in the ratio of 1:10 for pressure coil 

Explain magnetic effect employed in measuring instrument.

Description : Explain magnetic effect employed in measuring instrument.

Last Answer : Magnetic Effect:  I) In PMMC meters:  ➢ When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current ... field it experiences a mechanical force.  Examples: Electrodynamometer type instruments, Induction type instrument. 

Why energy meter is integrating type measuring instrument?

Description : Why energy meter is integrating type measuring instrument?

Last Answer : Energy Meter is Integrating Type Measuring Instrument: Energy meter is used for measurement of energy, which is obtained by integration (summation) of power supplied over the particular time duration, hence it the integrating type measuring instrument. 

When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially

Description : When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially short circuited because  (A) Cables have a low value of capacitance which draws a high ... high value of charging current (D) Cables have a low value of capacitance and initial resistance

Last Answer : When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially short circuited because Cables have a high value of capacitance which draws a high value of charging current

The desirable static characteristics of a measuring system are?

Last Answer : The desirable static characteristics of a measuring system are accuracy, sensitivity and reproducibility.

For measuring a very high resistance we should use?

Last Answer : For measuring a very high resistance we should use Meggar.

For measuring current at high frequency we should use?

Last Answer : For measuring current at high frequency we should use thermocouple instrument.

String efficiency is used for measuring the?

Last Answer : String efficiency is used for measuring the degree of utilization of SCR.

List of Scientific Instruments

Description : List of Scientific Instruments

Last Answer : Hydrometer measures humidity Barometer measures atmospheric pressure Purity of milk is measured by lactometer Fathometer measures the depth of oceans. Sextant is used for measuring ... regulate the temperature to a particular degree. Viscometer: is an instrument to measure viscosity.

Compare analog and digital instruments .

Description : Compare analog and digital instruments .

Last Answer : Parameter Analog Instrument Digital Instrument  1 Principle The instrument that displays analog signals is called as on analog instrument.  The instrument that displays ... , etc. Logical analyzer, signature analyzer, computers, microprocessor based instruments, etc. 

Advantages of digital instruments

Description : Advantages of digital instruments

Last Answer : 1. They are having high input impedance, so there is no loading effect 2. They are having higher accuracy 3. An unambiguous reading is obtained 4. The output can be interfaced with external equipment 5. They are available in smaller size . 

State the effect of dead zone on instruments.

Description : State the effect of dead zone on instruments.

Last Answer : It is the largest change in input during which the output remains constant. So during dead zone, even if input changes, output remains the same.

Define: i) Range ii) Span of instruments

Description : Define: i) Range ii) Span of instruments

Last Answer : i) Range: It is defined as the difference between Greatest and Smallest value of the data or reading of the instrument.  ii) Span: It is defined as the algebraic difference between the upper and lower range values

State the meaning of secondary instrument. Classify secondary instruments.

Description : State the meaning of secondary instrument. Classify secondary instruments.

Last Answer : Secondary instruments: - Gives reading directly of the quantity being measured. - Calibrated with respect to absolute instruments  Classification of Secondary instruments:  1. Depending on the ... on permissible error: i) Standard meters ii) Substandard meters iii) First grade instruments.

Compare primary and secondary instruments.

Description : Compare primary and secondary instruments.

Last Answer : Primary instruments  Secondary instruments  Gives magnitude of quantity in terms of physical constants of instrument  Gives reading directly of the quantity measured.  Need no calibration  ... .  e.g. magnetic meter, induction meter, hotwire meter and electrostatic meter 

State the material used for moving coil and former for PMMC instruments.

Description : State the material used for moving coil and former for PMMC instruments. 

Last Answer : Material Used for Moving Coil and Former for PMMC Instruments:  Material used for moving coil: Copper  Material used for Former: Aluminium

Permanent magnet moving coil instruments are used for

Description : Permanent magnet moving coil instruments are used for

Last Answer : PMME are mostly used for measuring voltage and current.

The use of _____ instruments is merely confined within laboratories as standardising instruments.

Description : The use of _____ instruments is merely confined within laboratories as standardising instruments.

Last Answer : The use of absolute instruments is merely confined within laboratories as standardizing instruments.

Commonly used instruments in power system measurement are?

Last Answer : Commonly used instruments in power system measurement are induction.

Operating torques in analogue instruments are?

Last Answer : Operating torques in analogue instruments are deflecting, control and damping.

The power factor of a single phase load can be calculated if the instruments available are?

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.

The switch board instruments?

Last Answer : The switch board instruments should be mounted in vertical position.

In majority of instruments damping is provided by?

Last Answer : In the majority of instruments, damping is provided by eddy currents.

According to application, instruments are classified as?

Last Answer : According to application, instruments are classified as switch board, portable.

The use of which instruments is merely confined within laboratories as standardizing instruments?

Last Answer : The use of absolute instruments is merely confined within laboratories as standardizing instruments.

What do you mean by secondary instruments?

Description : What do you mean by secondary instruments?

Last Answer : The instruments which will give the direct readings are called secondary instruments

Standard Commands for Programmable Instruments (SCPI)

Description : Standard Commands for Programmable Instruments (SCPI)

Last Answer : Standard Commands for Programmable Instruments (SCPI) SCPI stands for Standard Commands for Programmable Instruments it is often pronounced as Skippy. SCPI is a instrument language that control the ... is for storing data in instrument. Display : for presentation.

Does anyone know how one gets to perform at Carnegie Hall?

Description : Does anyone know how one gets to perform at Carnegie Hall?

Last Answer : Practice. Practice. Practice.

What is an object/item/instrument that you feel one with?

Description : What is an object/item/instrument that you feel one with?

Last Answer : My clarinet.

Why don't violins have frets?

Description : Why don't violins have frets?

Last Answer : answer:To allow the player to hit quarter and half notes. It also allows the instrument to be tuned in non-equal intervals. Also, you can get fretted violins (supposed to be good for new players).

This may seem a stupid question, but how does a left-handed string player play in an orchestra?

Description : This may seem a stupid question, but how does a left-handed string player play in an orchestra?

Last Answer : They are generally seated at the other end of the line. if there are more than one, then they sit together.

How do I sell a cello in the bay area or seattle area?

Description : How do I sell a cello in the bay area or seattle area?

Last Answer : I’ve always had good luck with Craigslist, but as on any such site, you’ve got to be really careful to find out the buyer is legit. I NEVER sell stuff anymore to anyone outside my immediate geographical area.

What banjo should I buy?

Description : What banjo should I buy?

Last Answer : Buy one that sounds good to you. It’s the same for any instrument.

How much should a good 4/4 violin cost for a beginner?

Description : How much should a good 4/4 violin cost for a beginner?

Last Answer : Even for a beginner a good one will be upwards of 700–800 dollars. You could find one for 50–100 I’m sure, but it would not sound good at all and you don’t want to start learning the notes with a bad sounding instrument as that is what your ear will get used too.

Has anyone learned to play a musical instrument when you were older? I'm interested in those where this would have been their first musical instrument.

Description : Has anyone learned to play a musical instrument when you were older? I'm interested in those where this would have been their first musical instrument.

Last Answer : Define “older” I changed instruments later in life from guitar to violin… I suppose that does not count though.