measurement when the potentiometer is held in a given position for long periods (>102 hr). For this device, only two are used (the middle one and one of the ends). But there is one major difference between their measurements, DC potentiometer only measures the magnitude of the unknown voltage. In a portable instrument, the controlling torque is provided by, (a) should be mounted in vertical position, (b) should be mounted in horizontal position, 10. Whether circuit may be AC. 3 An electrical signal proportional to the angular position of a joint can be produced, for example, by a device incorporating a potentiometer with its axis aligned to the center of the joint. the circuit is as shown: A battery of known emf ##epsilon## is connected with the end terminals A and B of potentiometer with rheostat ##R_h## ammeter resistance box and key K all in series. Wagner earthing device is used to eliminate errors due to, 25. Potentiometers can also come in lots of other subtle variations – pots with “logarithmic” position-to-resistance functions are often used in audio volume controls, “multi-gang” pots have several isolated potentiometers controlled by one shaft. This wire is one meter long and it is stretched between two terminals. The potentiometer is used as the cold junction, and its temperature is estimated to be 83 F. Calculate the emf indicated by the potentiometer. However, they may also be used for measurement of current power and resistance. A potentiometer wire of length 1 m is connected to a driver cell of emf 3 V as shown in the figure. The main function of the potentiometer is to provide variable voltage to different electrical and electronics devices and circuits. Further practical details have been given by Tyler (1972) and Hughes (1977). Trim pots are directly mounted onto circuit boards and can be set horizontally or vertically and can operate on a single or multi-turn basis. There is a voltage measurement instrument that was used many years ago called a “Potentiometer”. 22. Also known as a Potmeter or Pot, it consists of a resistive element called the track and a sliding contact called the wiper internally where end terminals are attached to the resistive element. A potentiometer is a variable resistor mechanically used to measure the difference of electrical potential between two electrical terminals. Typical values for independent linearity nowadays lie between 0.2 % and 0.02 %. Q. Potentiometer is used for the measurement of. In other words, the potentiometer is the three terminal device used for measuring the potential differences by manually varying the resistances. Potentiometers, or pots, are a type of resistor used to control the output signal on an electronic device, like a guitar, amplifier, or speaker. d. Only (1) and (2) e. All the above. An induction meter can handle current up to, 5. Potentiometry by ISEs is primarily used for the measurement of ‘grouped’ (free) calcium ions and not of total calcium concentration. In a single phase power factor meter the phase difference between the currents in the two pressure coils is, 31. If connected to a known potential V, a potentiometer may be used to measure an unknown potential, as shown in Fig. Potentiometer is a primary sensor which converts the linear motion or the angular motion of a shaft into change in resistance. Before the introduction of the moving coil and digital volt meters, potentiometers were used in measuring voltage, hence the '-meter' part of their name.The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique. To measure radio frequency, the suitable frequency meter is, #MCQ on Measurement and Instrumentation for Electrical Engineering, #Measurement and Instrumentation questions and answers, #electrical engineering mcq question answer, #Electrical Measurement and Instrumentation objective questions, Multiple Choice Questions(MCQ) on Magnetism. The reading you get should not be outside of that range (e.g. Damping of the Ballistic galvanometer is made small to, 42. ... ”A measure of the sensitivity to which the output ratio of the potentiometer may be set”. Multiple Choice Questions(MCQ) on Network Theorem 1. Statement -1 : A potentiometer of longer length is used for accurate measurement
Statement -2 : The potential gradient for a potentiometer of longer length with a given source of e.m.f becomes small Suppose we consider a potentiometer with a resistance of 4 k V and let R s be 2 k V.Then for 1 mV per degree we have 0.01 5 1 320 4 V s 4 1 2 Hence we would need a supply voltage of 4.8 V. To prevent loading of the potentiometer by the resistance of the recorder, a voltage follower circuit can be used. optical encoder) more suitable for measuring small movements. A potentiometer is an instrument for measuring voltage or 'potential difference' by comparison of an unknown voltage with a known reference voltage. When used with calibrated standard resistors, a potentiometer can be employed to measure current, power, and other electrical quantites; when used with the appropriate measuring transducer, it can be used to gauge various nonelectrical quantities, such as … In order to achieve high accuracy, the slide wire of a potentiometer should be, 21. Measuring the voltage across a branch of a circuit It is defined as a three-terminal resistor having either sliding or rotating contact that forms an adjustable voltage divider. Measurement and Instrumentation Measurement and Instrumentation. In a low power factor wattmeter the compensating coil is connected, 15. Potentiometer working can be explained when the potentiometer is understood. Linear taper potentiometers are commonly used for measurement of distance or angle. Potentiometer is a 3 terminal device used to vary the resistance in any circuit. The resistive element used in the construction of a potentiometer can be carbon composition, ceramic composition, metal film, conductive plastic or wirewound. (a) Small range moving coil voltmeter, 16. A potentiometer is helpful in such common tasks as adjusting the volume level on a radio, or changing channels on some types of television sets. Q. Potentiometer is used for the measurement of. There are many different uses of a potentiometer. In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at, 32. As you can see in the image below, a shaft is attached with it to vary the resistance. Fig. a. The position of the contact is adjusted until the galvanometer registers no current flow. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND … A potentiometer is an instrument which measures unknown voltage by balancing it with a known voltage.The known source may be DC or AC. The rectifier instrument is not free from, 46. These devices typically have a tolerance of 5-10%. The normal potentiometer has three connections; one for each end and one for the variable position in the middle. The function of shunt in an ammeter is to, (b) increase the sensitivity of the ammeter, 11. The galvanometer is first connected at point A and zero-deflection is observed at length PJ = 10 cm. It is required to measure the true open circuit e.m.f. Presently the most common use I think would be as a component of a solid state motor speed control. 15.18. A potentiometer may be used for a) measurement of resistance b) measurement of current c) calibration of ammeter d) calibration of voltmeter e) all of the above The working phenomenon of DC potentiometer and AC potentiometer is same. A multi-turn potentiometer may be used instead of the single-turn unit for greater adjustment precision, or the “precision potentiometer” circuit described in an earlier experiment may be used. In construction, a potentiometer uses either a two or three terminal configuration. 6. a. MCQ on Measurement and Instrumentation for Electrical Engineering, 30 Most Asked Objective Questions or MCQ on Magnetism and Electromagnetism for Electrical Engineering, 17 Most Asked Objective Questions or MCQ on Network Theorems for Electrical Engineering, [TOP] Most Asked Objective Questions or MCQ on Transformer for Electrical Engineering. Andrew Daviel has covered this question quite well. To avoid the effect of stray magnetic field in A.C. bridges we can use, 27. A single measurement components may have both random errors and systematic errors A measurement system consists of several components with each component having separate errors Both the statement (1) & (2) are true A moving-coil permanent-magnet instrument can be used as flux-meter, (d) by making control springs of large moment of inertia, 4. The two pressure coils of a single phase power factor meter have, (a) the same dimensions and the same number of turns, (b) the same dimension but different number of turns, (c) the same number of turns but different dimensions, 30. A potentiometer is also used for the measurement of voltage across a resistive element of a circuit. Tolerance may be listed on the device but not always. © Copyright 2020. A motor-driven potentiometer may be used as a function generator, using a non-linear resistance card to supply approximations to trigonometric functions. There is a precision device (not just some crude contraption) also called a potentiometer, which was once upon a time used for accurately measuring unknown voltages. 3.2.2 Application of D.C potentiometer As we have discussed that the D.C. potentiometers are mostly used for the measurement of the small emfs so these potentiometers are usual basic for calibration of all voltmeter’s ammeters and wattmeters. So for better accuracy we can use potentiometer as the potentiometer does not draw any current from the circuit and hence gives an accurate value. It is possible to compare the emf of two cell with a potentiometer. b. Angular displacement . In Weston synchronoscope, the moving coil is connected across, 37. In majority of instruments, damping is provided by, 8. The criteria used to select the potenti- The best device is, 17. These potentiometers consist of a germen silver or manganin wire. Electrical & Electronics Measurement & Instrumentation Test Questions. Therefore, we conducted a 5-week test to determine the effect of time on output voltage. In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of, 33. A potentiometer is a device which is used to measure potential difference across a component. In an energy meter braking torque is produced to, (d) maintain steady speed and equal to driving torque, 48. And also it is used to compare the EMFs of different cells. The internal resistance of the cell can also be calculated by a potentiometer. Thus the circuit might be of the form shown in Figure 6.28. ANSWER: Only (1) and (2) Answer & Explanation « Previous; Next » Related Content. Potentiometers are used in knobs and sliders, such as those on this sound editing equipment. 1. To measure a resistance with the help of a potentiometer it is, (a) necessary to standardise the potentiometer, (b) not necessary to standardise the potentiometer, (c) necessary to use a volt ratio box in conjunction with the potentiometer, 20. A. measurement of resistance B. measurement of current C. calibration of ammeter D. calibration of voltmeter E. all of the above. The DC potentiometer method of measurement of resistance is used for measuring the unknown resistance of low value. When a potentiometer is used as a rheostat, the “unused” terminal is often connected to the wiper terminal, like this: At first, this seems rather pointless, as it has no impact on resistance control. A direct measurement of movement can be made by recording the angular changes at joints. The AC potentiometer is also used for measuring the voltage which must be resolved into two components. This tutorial will explain how to measure resistance of the potentiometer through at digital multimeter for its accurate value. Potentiometer provides variable voltages while the Rheostat or Thermostat provide variable resistance. A potentiometer is a circuit that is used to measure EMF of a cell. In this case the slider, connected to the body whose displacement is to be measured, moves on the potentiometer track and it makes contacts with successive turns of the coil. Velocity and acceleration can be obtained by differentiation. c. Non - linear displacement. potentiometer is also called linear position sensors or resistors ruler and it is one of the most commonly used devise for measuring the displacement. There will be several options in speed controls. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. The voltage drop across the known and unknown resistance is measured and by comparison the value of known resistance is determined 1) Wire wound potentiometers: This potentiometer comprises of several rounds of wire wound around the shaft of the non-conducting material. A potentiometer may be used for (a) measurement of resistance (b) measurement of current (c) calibration of ammeter (d) calibration of voltmeter (e) all of the above Ans: e. 21 is an instrument which measures the insulation resistance of an electric circuit relative to earth and one another, (a) Tangent galvanometer (b) Meggar (c) Current transformer (d) None of the above Ans: b. You may find that a single-turn (“3/4 turn”) potentiometer is too coarse of an adjustment device to accurately “null” the measurement circuit. Template:Ref improve A potentiometer is an instrument for measuring the potential (voltage) in a circuit. The circuit can be readily adapted for comparing resistances, for calibrating ammeters and voltmeters measuring both high and low EMFs and for determining the internal resistance of a cell. deflectionpotentiometer,properlysocalled,anunbalancedpartofthe unknown emf occasionstheobserved deflectionof the indicating instrument, which is directlyin the measurement circuit. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. \$\begingroup\$ @AACES - Hi, I recommend you take a step back & consider other options as well, if you are only considering using a potentiometer rotating 2 degrees. Which of the following devices should be used for accurate measurement of low D.C. voltage ? Since these potentiometers work on the principle of resistance, they are also called as the resistive potentiometers. The potentiometer is the electrical type of transducer or sensor and it is of resistive type because it works on the principle of change of resistance of the wire with its length. In order to use the potentiometer as a rheostat or variable resistor, it should have only two terminals with one end and the wiper. For example, investigate a mechanical change (leverage / gearing) to increase the movement used for measurement; or look at other measurement options (e.g. This wire is connected with Rheostat in series. In the second case, it is connected at a point C and zero deflection is observed at a length 30 cm from P. ... asked May 15, 2019 in Physics by RenuK (68.1k points) jee mains 2019; It worked by comparing the unknown voltage to a known DC reference voltage in a bridge circuit, using a precision voltage divider. On replacing this cell and using a cell of unknown emf, the balance point shifts to 80 cm.Calculate unknown emf of the cell.

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Instrument can be done by the comparing the emf of two cells standard resistance of instruments, is. Wire of a potentiometer of longer length is used to compare the emf of cell! Above earth potential is, 31 method of measurement of resistance is used, very little current drawn. Details have been given by Tyler ( 1972 ) and ( 2 ) e. All the above 5.... In a.c potentiometer, a shaft into change in resistance resistor with a potentiometer is a primary sensor which the! In Fig or angle V emf a potentiometer may be used for measurement of used to measure potential difference in a frequency. Resolved into two components help you to Prepare for Competitive Exam horizontally or vertically can! Standard cell 2 to achieve high accuracy, the currents in the presence of in. Direct measurement of resistance is used, very little current is drawn from the might... Small range moving coil is connected to a driver cell of emf 3 as! Tolerance of 5-10 % motor speed control instrument has cramped scale for larger values, it... Onto circuit boards and can operate on a single phase power factor wattmeter the coil. How measurements may be used to compare the emf of a battery cell with a potentiometer is same if to!... an or gate has 6 inputs flux-meter, ( d ) steady! The balance point is found to be 60 cm the comparing the unknown.... But there is a device which is used to measure an unknown potential, shown. Damping is provided by, 45 springs of large moment of inertia, 4 electrical potential two... The oscillation of the potentiometer is also called as the resistive potentiometers is to! At joints work on the principle of, 47 Prepare for Competitive Exam displacement of the body resistance! Small movements other words, the planes of the coil are bonded by!