akt: February 2013

Thursday, 28 February 2013

Magnetic circuits Assignment: course Basic Electrical Engineering

Assignment # 1

Basic electrical engineering

Q1. Define the following terms as applied to a magnetic circuit:

Permeability, Magneto-Motive Force (MMF), Reluctance, Permeance, Reluctivity

Q2. Give analogy between electric & magnetic circuits.

Q3. Explain briefly the following two types of losses which occurs in magnetic materials: hysteresis losses, eddy current losses

Q4. What do you understand by electromagnetic induction?

Q5. Explain briefly faradays first & second laws of electromagnetic induction.

Q6. State and explain Flemings right hand rule.

Q7. What is lenz’s law?

Q8. What is the difference between the dynamically and statically induced emf?

Q9. A three phase load consists of three similar inductive coils, each of 50 Ω and inductance 0.3 h. the supply is 415 v, 50 hz. Determine line current, power factor, total power when load is star connected and delta connected.

Monday, 25 February 2013

Matlab code for famous Mexican hat

code

% program to plot Maxican hat

[x,y] = meshgrid(-8:0.5:8);
r = sqrt(x.^2+y.^2)+eps;
z = sin(r)./r;
surfc(z), shading flat
axis off

Thursday, 21 February 2013

Instrumentation and Measurement Objection Question book bank

(1) Instrument is a device for determining

(a) the magnitude of a quantity

(b) the physics of a variable

(d) both (a) and (b)

(2) Electronic instruments are preferred because they have

(a) no indicating part

(b) low resistance in parallel circuit

(d) high resistance in series circuit

(e) no passive elements.

(3) A DC wattmeter essentially consist of

(a) two ammeters

(b) two voltmeters

(d) a current and potential transformer

(4) Decibel is a unit of

(a) power

(b) impedance

(d) power ratio

(5) A dc voltmeter may be used directly to measure

(a) frequency

(b) polarity

(d)power

(6) An accurate voltmeter must have an internal impedance of

(a) very low value

(b) low value

(d) very high value

(7) The insulation resistance of a transformer winding can be easily measured with

(a) Wheatstone bridge

(b) megger

(d) voltmeter

(8) A 100 V voltmeter has full-scale accuracy of 5%. At its reading of 50 V it will give an error of

(a) 10%

(b) 5%

(d) 1.25%

(9) You are required to check the p. f. of an electric load. No p.f. meter is available. You would use:

(a) a wattmeter

(b) a ammeter, a voltmeter and a wattmeter

(d) a kWh meter

(10) The resistance of a field coil may be correctly measured by using

(a) a voltmeter and an ammeter

(b) Schering bridge

(d) a Maxwell bridge

(11) An analog instrument has output

(a) Pulsating in nature

(b) Sinusoidal in nature

(d) Independent of the input quantity

(12) Basic charge measuring instrument is

(a) Duddel's oscillograph

(b) Cathode ray oscillograph

(d) Bailastic Galvanometer

(e) Battery Charging equipment

(13) A.C. voltage can be measured (using a d.c. instrument) as a value obtained

(a) by subtracting the d.c. reading from it's a.c. reading.

(b) Using the output function of the multimeter

(d) By using a parallel capacitor with it

(e) None of the above

(14) A moving coil permanent magnet ammeter can be used to measure

(a) D. C. current only

(b) A. C. current only

(d) voltage by incorporating a shunt resistance

(e) none of these

(15) Select the wrong statement

(a) the internal resistance of the voltmeter must be high

(b) the internal resistance of ammeter must be low

(d) the check continuity with multimeter, the highest range should be used.

(e) In moving iron voltmeter, frequency compensation is achieved by connecting a capacitor across its fixed coil.

(16) Which of the following instrument is suitable for measuring both a.c. and d.c.

quantities.

(a) permanent magnet moving coil ammeter.

(b) Induction type ammeter.

(d) Moving iron repulsion type ammeter.

(e) Moving iron attraction type voltmeter.

(17) Swamping resistance is used in moving coil instruments to reduce error due to

(a) thermal EMF

(b) temperature

(d) galvanometer sensitivity.

(18) A power factor meter is based on the principle of

(a) electrostatic instrument

(b) Electrodynamometer instrument

(d) Rectifier type instrument.

(19) A potentiometer recorder is used for

(a) AC singles

(b) DC signals

(d) time varying signals

(e) none of these.

(20) Transformers used in conjunction with measuring instruments for measuring purposes are called

(a) Measuring transformers

(b) transformer meters

(d) instrument transformers

(e) pulse transformers.

(21) Leakage flux in an electrical machine is measure by

(a) Ballistic galvanometer

(b) Flux meter

(d) Vibration galvanometer

(e) CRO

(22) A C.R.O. is used to indicate

(a) supply waveform

(b) magnitude of the applied voltage

(d) all of these

(e) Magnitude of the current flowing in it.

(23) An oscillator is a

(a) an amplifier having feedback network

(b) a high gain amplifier

(d) a untuned amplifier

(e) None of these

(24) Distortion can be measured by

(a) Wave meter

(b) Digital filters

(d) Bridge T filter circuit

(25) Series connected Q- meter is preferable for measurement of components having

(a) high impedance

(b) low impedance

(d) high frequency

(e) low capacitance

(26) A potentiometer is

(a) an active transducer

(b) a passive transducer

(d) a digital transducer

(e) a current sensing transducer

(27) The basic components of a digital voltmeter are:

(a) A/D converter and a counter

(b) A/D converted and a rectifier

(d) Ramp generator and counter

(e) Comparator

(28) Which of the following electrical equipment cannot convert ac into dc

(a) diode

(b) converter

(d) mercury arc rectifier

(29) Voltage measurement are often taken by using either a voltmeter or

(a) an ammeter

(b) an ohmmeter

(d) a watt-meter

(30)The electric device which blocks DC but allows AC is called:

(a) capacitance

(b) inductor

(d) a watt-meter

(31 ) The range of an ammeter can be extended by using a

(a) shunt in series

(b) shunt in parallel

(d) multiplier in parallel

(32)A device that changes one form of energy to another is called

(a) rheostat

(b) oscillator

(d) varicap

(33) Aquadag is used in CRO to collect

(a) primary electron

(b) secondary electron

(d) none of above

(34) A vertical amplifier for CRO can be designed for

(a) only a high gain

(b) only a broad bandwidth

(d)all of the above

(35) One of the following is active transducer

(a) Strain gauge

(b) Selsyn

(d) Photo emissive cell

(36) The dynamic characteristics of capacitive transducer are similar to those of

(a) low pass filter

(b) high pass filter

(d) band stop filter

(37) Thermocouples are

(a) passive transducers

(b) active transducers

(d) output transducers

(38) The size of air cored transducers as compare to iron core counter part are

(a) bigger

(b) smaller

(39) From the point of view of safety, the resistance of earthing electrode should be:

(a) low

(b) high

(d) the value of resistance of electrode does not effect the safety

(40) In CRT the focusing anode is located

(a) between pre accelerating and accelerating anodes

(b) after accelerating anodes

(d) none of above

(41) Which transducer converts heat energy into electrical energy

(a) I. V. D. T.

(b) thermocouple

(d) none of the above

(42) Which of photoelectric transducer is used for production of electric energy by converting solar energy

(a) photo emission cell

(b) photo diode

(d) both (b) and (c)

(43) Which of the following instruments consumes maximum power during measurement?

(a) induction instruments

(b) hot wire instruments

(d) electrodynamometer instruments

(44) Which of the following meters has the best accurancy

(a) moving iron meter

(b) moving coil meter

(d) thermocouple meter

(45) The function of the safety resistor in ohm meter is to

(a) limit the current in the coil

(b) increase the voltage drop across the coil

(d) protect the battery

(46) Which of the following instruments is free from hysteresis and eddy current losses?

(a) M.l. instrument

(b) electrostatic instrument

(d)all of these

(47) The dielectric loss of a capacitance can be measured by

(a) Wien bridge

(b) Owen bridge

(d) Maxwell bridge

(48) Reed frequency meter is essentially a

(a) recording system

(b) deflection measuring system

(d) oscillatory measuring system

(49) In measurements made using a Q meter, high impedance elements should preferably be connected in

(a) star

(b) delta

(d) parallel

(50) A digital voltmeter measures

(a) peak value

(b) peak-to-peak value

(d) average value

Test your Instrumentation knowledge: Objective question

1. A balance beam scale uses which of the following units?
a. grams
b .pounds
c. ounces
d. kilograms
2. Which of the following would be about the height of the average doorway?
a. 2 meters
b. 2 centimeters
c. 2 millimeters
d. 2 kilometers
3. A series dissipative regulator is an example of a:
a. linear regulator
b. switching regulator
c. shunt regulator
d. dc-to-dc converter
4. Which of the following is a unit of mass in the metric system?
a. gram
b. milliliter
c. centimeter
d. pounds
5. What device is similar to an RTD but has a negative temperature coefficient?
a. Strain gauge
b. Thermistor
c. Negative-type RTD
d. Thermocouple
6. The resistive change of a strain gauge
a. is based on the weight placed upon it, but can be many thousands of ohms
b. is usually no more than 100 omega.
c. is based on the gauge factor, but is typically less than an ohm
d. has a positive temperature coefficient
Objective Type Questions
Instrumentation System & Devices (IDS)
2
7. The output voltage of a typical thermocouple is
a. Less than 100 mV
b. Greater than 1 V
c. Thermocouples vary resistance, not voltage.
d. None of the above
8. The connections to a thermocouple
a. Can produce an unwanted thermocouple effect, which must be compensated for
b. Produce an extra desirable thermocouple effect
c. Must be protected, since high voltages are present
d. Produce an extra desirable thermocouple effect and must be protected, since high
voltages are present
9. What is the zero-voltage switch used for?
a. To reduce radiation of high frequencies during turn-on of a high current to a load
b. To control low-voltage circuits
c. To provide power to a circuit when power is lost
d. For extremely low-voltage applications
10. Temperature sensing can be achieved by the use of
a. Thermocouples
b. RTDs
c. thermistors
d. All of the above
11. The purpose of compensation for a thermocouple is
a. to decrease temperature sensitivity
b. to increase voltage output
c. to cancel unwanted voltage output of a thermocouple
d. used for high-temperature circuits
12. The change in value of an analog signal during the conversion process produces what is
called the
a. Quantization error
b. Resolution error
c. Nyquist error
d. Sampling error
Objective Type Questions
Instrumentation System & Devices (IDS)
3
13. Which of the following performance specifications applies to a sample-and-hold circuit?
a. Aperture time
b. Aperture droop
c. Feedback
d. Acquisition jitter
14. RTDs are typically connected with other fixed resistors
a. In a pi configuration
b. In a bridge configuration
c. And variable resistors
d. And capacitors in a filter-type circuit
15. Holding current for an SCR is best described as
a. The minimum current required for turn-off
b. The current required before an SCR will turn on
c. The amount of current required to maintain conduction
d. The gate current required maintaining conduction
16. What is the moving part of a linear variable differential transformer?
a. Primary
b. Secondary
c. Diaphragm
d. Core
17. What does a Hall Effect sensor sense?
a. Temperature
b. Moisture
c. Magnetic fields
d. Pressure
18. What causes the piezoelectric effect?
a. Heat or dissimilar metals
b. Pressure on a crystal
c. Water running on iron
d. A magnetic field
Objective Type Questions
Instrumentation System & Devices (IDS)
4
19. What type of application would use a photovoltaic cell?
a. An automobile horn
b. A TI 92 calculator
c. A magnetic field detector
d. A remote power source
20. Which is the seven-segment display?
21. A transducer's function is to:
a. Transmit electrical energy
b. Convert energy
c. Produce mechanical energy
d. Prevent current flow
22. Derived units are obtained from various combinations of
a. Electrical quantities
b. Fundamental units
c. Metric prefixes
d. International standards
23. Scientific notation is a method
a. of expressing a very large number
b. of expressing a very small number
c. used to make calculations with large and small numbers
d. All of the above
24. If you drop a 5 when rounding a number, you are using the
a. round-to-even rule
b. significant digit rule
c. round-off rule
d. retained digit rule
Objective Type Questions
Instrumentation System & Devices (IDS)
5
25. A measure of the repeatability of a measurement of some quantity is
a. error
b. precision
c. accuracy
d. significant
26. Another name for "fundamental units" is
a. base units
b. atoms
c. the metric system
d. letter symbols
27. When using the terms "accuracy" and "precision" for measurements
a. "precision" implies less measurement error than "accuracy"
b. "accuracy" implies less measurement error than "precision"
c. "precision" measures the repeatability of a measurement
d. both terms mean the same thing
28. The difference between scientific and engineering notation is
a. powers of ten representation
b. single vs. multiple digits before decimal point
c. groupings of multiples of three digits
d. All of the above
29. The digits in a measured number that are known to be correct are called
a. accuracy digits
b. significant digits
c. error digits
d. precision digits
30. Pico is what relation to micro?
a. one-tenth
b. one-hundredth
c. one-thousandth
d. one-millionth
Objective Type Questions
Instrumentation System & Devices (IDS)
6
31. Four terminal resistors are used for resistance values
a. Greater than 10 ohm
b. Greater than 1 ohm
c. Less than 1 ohm
d. Of the order of 1M ohm
32. The condition for a resistor to have the same value of resistance at medium frequencies
is as with D.C. is
a. CR ²=L
b. CR ²=2L
c. CR ²=WL
d. CR ²=2WL
33. Permeability is the inverse equivalent of which electrical term?
a. Voltage
b. Current
c. Resistance
d. Conductance
34. What is the flux density of a magnetic field whose flux is 3000 μWb and cross-sectional
area is 0.25 m ²?
a. 12,000 μ T
b. 83,330 μ T
c. 0 μ T
d. More information is needed in order to find flux density.
35. How much flux is there in a magnetic field when its flux density is 5000 mu.gifT and its
cross-sectional area is 300 mm ²?
a. 16.67 m Wb
b. 5.0 μ Wb
c. 3.0 m Wb
d. 1.5 μ Wb
36. What are the effects of moving a closed wire loop through a magnetic field?
a. A voltage is induced in the wire.
b. A current is induced in the wire.
c. The polarity across the wire depends on the direction of motion.
d. All of the above
Objective Type Questions
Instrumentation System & Devices (IDS)
7
37. The Hall Effect
a. is a phenomenon with no practical applications
b. is used in various sensor applications
c. can develop potentials of thousands of volts
d. is the basis for solar cell operation
38. A Hall Effect sensor
a. exists only in theory
b. is a non-contacting magnetic sensor
c. can operate only a few times before failure
d. produces very large voltages
39. Which two values are plotted on a B-H curve graph?
a. Reluctance and flux density
b. Permeability and reluctance
c. Magnetizing force and permeability
d. Flux density and magnetizing force
40. for turbulent flow, the velocity at the center is ____ times the mean velocity
a. 1.2
b. 2.2
c. 2
d. 3.333

Tuesday, 19 February 2013

See how much u know about Instrumentation Questions and Ans

1. What is air core inductance ?
The inductance that would be measured if the core had unity permeability and the
flux distribution remained unaltered. (A measure of the inductance of a coil
without a core).
2. What do you mean by Balance?
A weighing machine. The terms scale and balance are often used
interchangeably. a balance was a device that determined mass by balancing an
unknown mass against a known mass as with a 2 pan assay balance.
3. Define Viscosity.
It is a measure of fluidity of the system. Many fluids undergo continuous
deformation with the application of shearing stress.
4. Define Newtonian fluids
If the force flow relation is linear then the fluid is Newtonian .
5. Define Non Newtonian fluids
If the force flow relation is non linear then the fluid is Newtonian .
6. Define Kinematic Viscosity.
Ratio of absolute viscosity to the density of the fluid. V= μ cm2 /V sec
7. Define Specific Viscosity.
Ratio of absolute viscosity of the fluid to the absolute viscosity of a standard fluid at
the same temperature. μs = μ / μh
8. Define Relative Viscosity.
Ratio of absolute viscosity of the fluid at a given temperature to the absolute
viscosity of a standard fluid at 20°c.
9. Define Viscosity index
It is an empirical number that indicates the effect of change of temperature on
viscosity if a fluid.
10. Define fluidity.
It is the reciprocal of viscosity. It is unit is 1/ poise.
11. Define Humidity.
It is basically moisture content in air or it is the quantity of water vapour retained by
gas.
12. Define Absolute Humidity.
Weight of water vapour in unit wait of gas.
1. H=Wr / Wg
13. Define Specific Humidity.
It is weight of vapors in unit weight of mixture.
INDUSTRIAL INSTRUMENTATION
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14. Define Relative Humidity.
This is the ratio of moisture content of gas to maximum moisture content of the gas
at that temperature.
15. Define various units of Humidity.
Vppm = parts per million / volume.
G/ kg = weight concentration
Relative humidity = in %
Dew point in °C.
16. Define Hygrometer.
Used to measure the moisture content in air. It also used to measure humidity.
17. What is the basic principle of Hygrometer.
It consist of mechanical device measuring the dimension change of humidity
sensitive materials like animal hair, animal membrane , paper etc.
18. Define Moisture.
Defined as the amount of water absorbed by solids or liquids.
19. What are the different types of viscometer?
Say bolt viscometer
Rotameter type
Consistency meters.
20. What is Psychrometer?
Psychrometer is a device that uses the bulb thermometers to measure humidity. It is
also used in air conditioning systems for maintaining humidity.
21. What are the different types of hygrometer?
Hair hygrometers
Wire electrode hygrometers
Electrolysis type hygrometers
Resistive type
Capacitive type
Microwave reflector
22. Explain the principle of saybolt viscometer.
As the viscosity of the fluid varies , the flow rate and hence time taken to drain the
fluid through the capillary tube varies. The time indicates the viscosity and is
denoted by say bolt number.
23. What is meant by consistency?
General term for viscosity and more often used in connection with Non-Newtonian
fluids.
24. What is Celsius or Centigrade?
A temperature scale defined by 0°C at the ice point and 100°C at the boiling point of
water at sea level.
25. Define Absolute Zero
Temperature at which thermal energy is at a minimum. Defined as 0 Kelvin,
calculated to be –273.15°C or –459.67°F.
INDUSTRIAL INSTRUMENTATION
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26. What is Ambient Temperature?
The average or mean temperature of the surrounding air which comes in contact with
the equipment and instruments under test.
27. Define Boiling Point
The temperature at which a substance in the liquid phase transforms to the gaseous
phase; commonly refers to the boiling point of water which is 100°C .
28. What is Calorie?
The quantity of thermal energy required to raise one gram of water 1°C at 15°C.
29. Define Exothermic process?
A process is said to be exothermic process when it releases heat.
30. What is Dissipation Constant?
The ratio for a thermistor which relates a change in internal power dissipation to a
resultant change of body temperature.
31. What is Fahrenheit?
A temperature scale defined by 32° at the ice point and 212° at the boiling point of
water at sea level.
32. Define Freezing Point
The temperature at which a substance goes from the liquid phase to the solid phase.
33. What is Kelvin?
Kelvin is the unit of absolute or thermodynamic temperature scale based upon the
Celsius scale with 100 units between the ice point and boiling point of water. 0°C =
273.15K. Symbol K.
34. What is Joule?
The basic unit of thermal energy.
35. Define Heat
Heat is thermal energy. Heat is expressed in units of calories or BTU’s.
36. What is Heat Sink?
A body which can absorb thermal energy.Practicaly, A finned piece of metal used to
dissipate the heat of solid state components mounted on it.
37. What is Heat Transfer
The process of thermal energy flowing from a body of high energy to a body of low
energy. Transfer by Means of :conduction; the two bodies contact. Convection; a
form of conduction where the two bodies in contact are of different phases, i.e. solid
and gas. Radiation: all bodies emit infrared radiation.
38. What is Latent Heat?
The amount of heat needed to convert a pound of boiling water to a pound of steam.
39. State Limits of Error
A tolerance band for the thermal electric response of thermocouple wire expressed in
degrees or percentage defined by ANSI specification MC-96.1 (1975).
40. What is Loop Resistance?
The total resistance of a thermocouple circuit caused by the resistance of
thermocouple wire.Usually used in reference to analog pyrometers which have
typical loop resistance requirements of 10 ohms.
INDUSTRIAL INSTRUMENTATION
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41. What is Maximum Operating Temperature?
The maximum temperature at which an instrument can be safely operated.
42. What is Mean Temperature?
The average of the maximum and minimum temperature of a process equilibrium.
43. Define Melting Point
The temperature at which a substance transforms from a solid phase to a liquid
phase.
44. What is Negative Temperature Coefficient?
A decrease in resistance with an increase in temperature.
45. Define Resistance Temperature Characteristic
A relationship between a thermistor’s resistance and the temperature.
46. What is Specific Heat?
The ratio of thermal energy required to raise the temperature of a body 1° to the
thermal energy required to raise an equal mass of water 1°.
47. What is RTD?
Resistance temperature detector.
48. What is Thermal Coefficient of Resistance?
The change in resistance of a semiconductor per unit change in temperature over a
specific range of temperature.
49. What is Thermal Conductivity?
The ability of a material to conduct heat in the form of thermal energy.
50. What is a Thermistor?
A temperature-sensing element composed of sintered semiconductor material which
exhibits a large change in resistance proportional to a small change in temperature.
Thermistors usually have negative temperature coefficients.
51. What is a Thermocouple?
The junction of two dissimilar metals which has a voltage output proportional to the
difference in temperature between the hot junction and the lead wires (cold junction)
52. What is Zero Power Resistance?
The resistance of a thermistor or RTD element with no power being dissipated.
53. what is Pressure?
Pressure is the amount of force applied to a unit area; Force divided by Area =
Pressure; the SI unit for pressure is the Pascal (Pa) which is derived from Kilogram
per Metre Squared (kg/m2).
54. what isAbsolute Pressure?
Absolute Pressure is one which is measured relative to a perfect vacuum.
55. define Barometric Pressure
Barometric Pressure or Atmospheric Pressure is the total outside air pressure
measured with reference to absolute vacuum. The pressure varies depending on
geographical location, altitude and local weather conditions.
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56. what is Bar?
Bar is a widely used metric unit of measure for pressure and 1 bar converts precisely
to 100000 Pascals.
57. what is Bonded Foil Strain Gauges ?
Bonded Foil Strain Gauges are metal based foil elements that are incorporated into
a flexible electrically insulating material which can then be bonded to a diaphragm
with adhesives. As pressure is applied to the diaphragm the strain gauge will deform
and its resistance will change.
58. what is Burst Pressure is a design safety limit which should not be exceeded. If
this pressure is exceeded it may lead to mechanical breach and permanent loss of
pressure containment.
59. what is Ceramic Pressure Sensors typically use diaphragms made from
Alumina (Al2O3) with a screen printed thick film strain gauge circuit. Ceramic
diaphragms are very inert and provide a high level of protection from aggressive
chemicals.
60. Compound Pressure Ranges are ones that combine positive and negative
pressure ranges into one pressure measurement device.
61. what is Differential Pressure is the difference between two separate pressure
points.
62. Digital Compensation is the process of collecting many measured points at
different pressures and temperatures and using this data to correct the output of a
pressure transducer so that the pressure accuracy and thermal errors can be
improved beyond what is practically achieved with analogue compensation.
63. Full Range Output or FRO is the maximum electrical output signal for an
analogue output pressure sensor.
64. Full Scale Output or FSO is the maximum electrical output signal for an
analogue output pressure sensor.
65. Gauge Reference Pressure is a pressure measured relative to atmospheric or
barometric pressure.
66. Hydrostatic Pressure is what is exerted by a liquid when it is at rest. The height
of a liquid column of uniform density is directly proportional to the hydrostatic
pressure.
67. what is Inch of Water Gauge or Inches of Water Column is an english and
american unit for measuring liquid level. 1 inch of water column at 4 degrees
celsius equals 249.089 Pascals.
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68. what is Long Term Stability or Long Term Drift is the amount of change of a
measured reading at exactly the same pressure and ambient conditions over a
given period of time which is typically quoted as an annual figure.
69. Measurement Precision is used to describe how close together a set of results
are and it means the same as non-linearity.
70. what is Negative Gauge Pressure or Suction Pressure is the difference in
pressure between any vacuum pressure and atmospheric pressure.
71. what is Non-Linearity is how much a set of recorded pressures deviate from the
best straight line and it is expressed as a percentage of full scale.
72. what is Overpressure or Proof Pressure is the maximum pressure that can be
applied to a pressure instrument without significantly affecting its reading
accuracy. Some manufacturers will state a maximum calibration shift following
an over-pressure condition where others will state that the specification is
unaffected.
73. what is Pressure Accuracy defines the limit that any pressure measurement
reading will deviate from the ideal point.
74. what is Pressure Transducer is any device that can convert a change in pressure
into a varying electrical signal.
75. Pressure Transmitter is a pressure transducer which has been combined with an
amplification circuit to allow the electrical signal to be sent over longer distances
without degradation.
76. Primary Pressure Standard are instruments that can measure pressure very
accurately by deriving a pressure reading from the fundamental components of
mass, acceleration and area.
77. what is PSI, Pounds per Square Inch or Pound Force per Square Inch is a
widely used British and American unit of measure for pressure.1psi converts to
6,894.76 Pascals.
78. what is Reference Pressure is the pressure present on the reverse or negative
side of a sensing diaphragm. For example the pressure reading will be zero when
the total pressure measured on the positive side of the diaphragm equals the
reference pressure.
79. what is Secondary Pressure Standards are instruments that cannot be used to
measure Force and Area directly to derive a measurement of pressure but are still
used as a traceable standard for calibrating other pressure instruments, e.g. an
Electronic Pressure Calibrator that uses a Pressure Transducer inside would be
classed as a Secondary Pressure Standard.
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80. what is Semiconductor Strain Gauges?
These are typically made from Silicon and have very high gauge factors
compared to metal foil strain gauges. Ions are implanted into the n type Silicon
substrate to create p type regions which are significantly more conductive than the
surrounding n type Silicon. A p-n junction,created which provides electrical
isolation for p-type region when reverse voltage is applied, thus creating isolated
resistive region that will change with applied stress.
81. Sealed Gauge Reference Pressure is a pressure measured relative to an
atmospheric or barometric pressure which has been sealed in a fixed closed
volume.
82. Span Output is the difference between the minimum and maximum output
signals of a pressure sensor.
83. Span Offset is the amount of deviation in maximum span output signal of a
pressure sensor from the ideal value at full scale pressure. The span offset is
normally expressed as percentage of full scale pressure or electrical units, e.g.
±0.5% FS or ±3mV.
84. what is Standard Atmosphere is a universally adopted standardized pressure
reading for barometric pressure at sea level and equals precisely 1013.25mb
absolute. Standard atmosphere is a particularly useful datum point in altitude
measurement since all altimeters are calibrated to this pressure.
85. Static Line Pressure is the total pressure present at a particular point along a
pressurized pipe. It is often quoted on the specifications for differential pressure
sensors as an indicator of the maximum pressure that can be applied to both the
high and the low side pressure ports at the same time. This should not be
confused with the over-pressure limit which is related to the differential pressure
range rather than the static line pressure.
86. what is Suction Pressure or Negative Gauge Pressure is the difference in
pressure between any vacuum pressure and atmospheric pressure.
87. Traceable Pressure Calibration means that the equipment which was used to
calibrate a pressure measuring device has been regularly calibrated by another
more accurate instrument for which its own calibration can be traced back either
indirectly or directly to a National Standards Laboratory e.g. National Physical
Laboratory in the UK.
88. Transducer is a device that converts a non-electrical change into an electrical
change.
89. Vented Gauge Reference Pressure or VG is a pressure measured relative to
"actual" atmospheric or barometric pressure.
INDUSTRIAL INSTRUMENTATION
D.JACKSON ,LECT,NICE,KUMARACOIL
90. Wheatstone Bridge Strain Gauge circuits are used extensively inside pressure
transducers to convert mechanical stress into an electrical output signal.
91. Zero Offset is the deviation in output or reading from the ideal point at zero
pressure.
92. Zero Tare is the operation of removing any Zero Offset to obtain the optimum
measurement at zero pressure.
93. Factory calibration: The tuning or altering of a control device by the
manufacturer to bring it into specification
94. Range: The limits within which a device or circuit operates or the distance over
which a transmitter operates reliably.
95. pH: An indication of the acidity or alkalinity of a solution. Units range from 0
(most acidic), to 7 (neutral), to 14 (most alkaline).
96. Linearity: The degree to which performance or response approaches the
condition of being linear. Expressed in percent.
97. Impedance: The opposition in an electric circuit to the flow of an alternating
current. It consists of ohmic resistance, inductive reactance, and capacitive
reactance.
98. what is Inch of Mercury?
It is a British and American unit of measure for pressure. 1 inch of Mercury at 0
degrees Celsius (32 deg F) equals 3386.39 Pascals.

Monday, 18 February 2013

How to have multiple plots and subplots in MATLAB figure window

http://youtu.be/yjlLx4KVtIs

Sunday, 17 February 2013

Revolving and bouncing heart animated in MATLAB

Saturday, 16 February 2013

Amazing MATLAB graphics

Solving multivariable equations with MATLAB: An example

function fcn = mul_equ(u)

x = u(1);
y = u(2);

fcn(1)= x.^2 +2*y.^2-5*x+7*y-40;
fcn(2) = 3*x.^2-y.^2+4*x+2*y-28;

%result = fsolve(@mul_equ,guess)
%[result,fval,exit flag,output]= fsolve(@mul_equ,guess)

output is:

>> [result,fval,exit flag,output]= fsolve(@mul_equ,guess)
Optimization terminated: first-order optimality is less than options.TolFun.

result =

2.6963 3.3655

fval =

1.0e-008 *

0.5849 -0.2216

exit =

1

flag =

iterations: 5
funcCount: 18
algorithm: 'trust-region dogleg'
firstorderopt: 1.3017e-007
message: 'Optimization terminated: first-order optimality is less than options.TolFun.'

output =

0.3926 20.4620
20.1779 -4.7310

Friday, 15 February 2013

MATLAB code for ball falling in circle 3D graphics

clf;
ellipsoid(1,4,9,1.1,2,3,20)
hold on
cylinder(10,20)
title('\fontsize{24}\bf\color{green}Drop the ball in the circle: MATLAB 3D GRAPHICS')
axis off

akt