S2: Change in resistance ? A movable soft iron core is placed inside the former. The primary winding is connected to an AC voltage source. In an LVDT, a complete isolation exists between input and output. The dynamic response is limited mechanically by the mass of the core and electrically by the frequency of applied voltage. Required fields are marked *. Sometimes, the performance of an LVDT is affected by vibrations. Self generating type transducers are _____ transducers. The amplified output can be measured by an electronic voltmeter which can be calibrated in terms of displacement. Lead Zirconate This residual voltage is generally less than 1% of the maximum output voltage in the linear range. The linear variable differential transformer transducer is A. Inductive transducer B. Non-inductive transducer C. Capacitive transducer D. Resistive transducer ... ANSWER: D. All of these . b) S2 is true & S1 is false The most widely used variable-inductance displacement transducer in Industry is a Linear Variable Differential Transformer (LVDT). b) Aluminium It is basically used to translate linear motion into electrical signals. Your email address will not be published. High Range: LVDT can be used for measurement of displacements ranging from 1.25 mm to 250 mm. E o = ES 1 – ES 2. ... A9 Inductive type Q10 How do we take the output of … d) S1 only, a) Steel sheets ... LVDTs, the two transducer secondaries are connected in opposition. c) Dialysate flow in artificial kidney c. Mutual inductance. The output voltage may be amplified by an amplifier. measured. The two secondary winding are connected in series opposition. b) Larger d) Change in resistivity, a) Exclusively used for construction of transducers Photo conductive cell consists of a thin film of, a) Quartz a) Active Quartz and Rochelle salt belongs to _______ of piezo-electric materials, a) Natural group If you continue to use this site we will assume that you are happy with it. d) Fiber group. a) Noise figure of 0 db. d) Copper, 20. b) Power a) Remains unaltered The coils are connected in series but in opposite phase , so that the output voltage is the difference between the two secondary voltages. Which of the following are piezo electric substances? c) Both S1 & S2 are true Linear displacement. The output voltage of secondary S 1 is ES 1 and that of secondary S 2 is ES 2. This is the null … b) Velocity c) Change in both length and diameter a) Strain gauge Whereas, the sensitivity of the RVDT is in the range of 2 to 3mv per volt per degree of rotation. b) Change in length of the wire Then the primary and secondary voltages of transformer are a. Both the secondary windings have the equal number of turns and are wound on both sides of the primary winding exactly alike. d) Pulse transducer. c) Force into a displacement c) Ferrite A Linear Variable Differential Transformer (LVDT) is common type of position sensor that converts the linear position or motion of a measured object to a proportional electrical output that can be read by operators and control systems. please update your website there are many answer is wrong. d) Inverse. ... the voltage in each secondary is equal in magnitude, but opposite in phase. S1: Transducer is a device which converts physical into electrical quantity a) S1 is true and S2 is false The output voltage of an LVDT is a linear function of core displacement within a limited range of motion (up to about 5 mm from the null position). Q11. Piezo electric crystal can produce an emf, a) When external mechanical force is applied to i d. Non – linearly … In a LVDT, the two secondary voltages a) Are independent of the core position b) Vary unequally depending on the core position c) Vary equally depending on the core position d) Are always in phase quadrature Ans : (b) 28. 4. Will we consider 3 different cases in order to understand the operation of an LVDT; Firstly, when the core is … Ideally, the output voltage at the null position should be equal to zero. For example, LVDT, a kind of inductive transducers, measures displacement in terms of voltage difference between its two secondary voltages. In a LVDT, the two secondary voltages a) Are independent of the core position b) Vary unequally depending on the core position c) Vary equally depending on the core position d) Are always in phase quadrature Ans : (b) 28. Time Response of Second Order Systems – IV. With a 0.25% full-scale linearity, it allows measurements down to 0.003 mm. It posses high sensitivity, typically about 40 V/mm. d) LVDT, 5. Inside the LVDT are three windings: one primary and two secondary coils that are 180° out of phase. S2: They are expensive, brittle and sensitive to temperature b) Silver electrode Ans : (b) ... AC Circuits Multiple Choice Questions. The frequency of the carrier should be at least ten times the highest frequency component to be measured. Secondary 1 + Secondary 2 The transfer of current between the primary and the secondaries of the LVDT displacement transducer is controlled by the position of a magnetic core called an armature. 1. The transfer of current between the primary and the secondaries of the LVDT displacement transducer is controlled by the position of a magnetic core called an armature. A strain gauge is a passive transducer and is employed for converting, a) Mechanical displacement into a change of resistance c) 25 micron to 60 micron It consists of two coils, primary coil, and secondary coil, the flux of the primary coil is induced in the secondary coil. E 0 = E s1 – E s2. The curve starts to deviate from a straight line, after this range. b) Finger movement c) 2 Photo emissive cathodes & 1 dynode d) Selenium. The distance of movement is determined by the differential voltage output of the two secondary coils (E1 – E2). Non – linear inductance. b) When radiant energy stimulates the crystal Fig: LVDT cross-section (source: te.com ) Linear Variable Differential Transformer (LVDT) is an inductive transducer that we discussed in the previous article. b) 25 micron (or) less b) Stable half cell potential c) S1 and S3 Since, both the windings are connected in the series opposition the output voltage of the winding (E o) will be the difference of the two voltages i.e. S2: Transducer is also called as sensor. This is done to get a single output voltage from the transducer. As the core moves in one direction away from the NULL position, voltage in one secondary increases while in the other secondary decreases i.e. d) Heart wall motion, a) Venous blood pressure So the differential output is, This equation explains the principle of Operation of LVDT. The secondary coils are connected in series to measure the sum of output voltage and derive the … d) 1 – A, 2 – B, 3 – C, 4 – D, 30. Q6) LVDT which is an instrument for the measurement of displacement, works on the principal of. b) Photo diode c) When external magnetic field is applied The LVDT (see Figure 15.3.2) is a position-to-electrical sensor whose output is proportional to the position of a movable magnetic core.The core moves linearly inside a transformer consisting of a center primary coil and two outer secondary coils wound on a cylindrical form. d) Both S1 & S2 are false, 27. c. Non – linear displacement. b) Lithium sulphate b) 1,3and4 47. c) Photo transistor The output voltage will be the difference between the two voltages (VS1-VS2) as they are combined in series. … Figure 9. a) S1 is true & S2 is false _________ is the example of photo emissive cell. The frequency of AC applied to the primary winding may be in the range of 50 Hz to 20 KHz. d) When the junction of two such crystals are heated, S1: Low fatigue life The LVDT is a transformer with one primary coil and two secondary coils, and the relative output between the two secondary coils is a function of the core’s position. Which of the following can be measured with the help of piezo electric crystal? These windings are connected in series opposition so that EMF induced in each coil opposes each other. Ans : (b) 28. Both the secondary windings (S1 & S2) has an equal number of turns and placed identically on either side of the primary winding in such a way that the net output will be the difference of the voltage of both secondary windings. Figure 1: Linear variable differential transformer (LVDT) The secondary windings are wound out of phase with each other. 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