Electrical Engineering Exam Prep by R. R. Gupta & James R. Claycomb

Author:R. R. Gupta & James R. Claycomb [R. R. Gupta and James R. Claycomb]
Language: eng
Format: epub
Publisher: Mercury Learning and Information
Published: 2019-10-14T16:00:00+00:00

Fig. Q. 118.

119.The backlash phenomenon occurs when

(a)gear teeth are big

(b)gear teeth are small

(c)whenever the direction of motion of gear system reverses

(d)whenever the gear teeth are not lubricated

120.A potentiometer cannot be used as a computation device.

(a)true

(b)false

121.The term conformity is related to a

(a)wattmeter

(b)motor

(c)potentiometer

(d)transformers

122.The desirable resolution of a potentiometer should be

(a)very high

(b)low

(c)zero

(d)infinity

123.The resolution of a potentiometer is dependent on the

(a)length of the wire

(b)material of the wire

(c)size of the wire only

(d)width of the wire and wire size

124.The deposited film type potentiometer has

(a)zero resolution

(b)infinity resolution

(c)adjustable resolution

(d)very small resolution

125.To minimize the loading effect on accuracy, a potentiometer should work

(a)into high impedance load

(b)into low impedance load

(c)into low resistance load

(d)into load of 500 ohms

126.Which of the following devices is used to avoid the loading effect on the potentiometer?

(a)Rheostat

(b)Battery

(c)Trimmer

(d)Current generator

127.If the excitation voltage across 1000 turns in a potentiometer is 5 volts, what will be the percentage resolution of the potentiometer?

(a)0.5%

(b)0.2%

(c)0.1%

(d)5%

128.The deposited film potentiometer has the following disadvantage:

(a)It has continuous surface and hence resistance cannot be changed

(b)Its resistance varies with the temperature

(c)It has infinite resolution

(d)It cannot be used as an error detector

129.The loading error in a potentiometer cannot be compensated by introducing intentional non-linearity.

(a)true

(b)false

130.A linear transformer is preferred to a potentiometer when used as an error detector because

(a)it is very cheap

(b)it eliminates the possibility of leading error

(c)it has high voltage sensitivity, infinite resolution and low friction level

(d)actuating signal is strong enough

131.The linear differential transformer is an

(a)electric device

(b)electromechanical device

(c)electromagnetic device

(d)electrostatic device

132.The linear differential transformer can be used to measure acceleration.

(a)true

(b)false

133.Which of the following devices is used to indicate the angular position of rudders in an aircraft?

(a)Potentiometer

(b)Linear differential transformer

(c)Rotary differential type transformer

(d)None of the above

134.Induction potentiometers are recommended for use in high impedance servo-controlled systems.

(a)true

(b)false

135.‘‘Microsyn’’ is the name given to a

(a)potentiometer

(b)resolver

(c)rotary differential transformer

(d)magnetic amplifier

136.‘‘Selsyn’’ is the trade name of

(a)synchros

(b)resolver

(c)linear

(d)gyroscope

137.The most common use of the synchros is as

(a)the error detector

(b)the transmission of angular data

(c)the transmission of arithmetic data

(d)any of the above

138.A synchro motor can be used as a synchro generator and the converse is also true.

(a)true

(b)false

139.A differential is used in a synchro differential unit for

(a)indicating the sum of rotation angle of the synchro generators only

(b)indicating the difference of rotation angle of two synchro generators only

(c)(a) and (b) both

(d)none of the above

140.The impedances of a stator and rotor windings of the control transformer are

(a)considerably higher than those of equivalent sized synchros

(b)considerably lower than those of equivalent sized synchros

(c)equal to those of equivalent sized synchros

(d)none of the above

141.The control transformer (synchro) should never be used to feed a low impedance load.

(a)true

(b)false

142.A synchro generator and motor is a

(a)3-phase A.C. device

(b)single phase A.C. device

(c)two phase A.C. device

(d)single phase D.C. device

143.Which of the following devices is used for conversion of co-ordinates?

(a)Microsyn

(b)Synchros

(c)Synchro resolver

(d)Synchro transformer

144.The thermocouple converts the temperature

(a)to voltage directly

(b)to current directly

(c)to A.C. power

(d)to D.C. power

145.Pressure errors can be measured by the

(a)synchro unit

(b)potentiometer

(c)thermocouple

(d)strain-gauge alone

(e)combination of differential bellows strain gauge

146.The synchro-generator-motor combination may be used to control the water level in the tank.

(a)true

(b)false

147.A simple lever device can be used as a mechanical position error detector.

(a)true

(b)false

148.The Pitot tube is used in airborne equipment to measure the

(a)volume of air

(b)temperature of the engine

(c)pressure of the air and fluid

(d)pressure of air only

149.

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