Control Systems Question & Answers June 5, 2021 By WatElectronics This article lists 100+ Control Systems MCQs for engineering students. All the Control Systems Questions & Answers given below includes solution and link wherever possible to the relevant topic. The connection of components together to perform a specific operation in which the output is controlled by input is known as a control system. The control systems are of two types open loop and close loop control systems. In an open-loop system, we just give input to a system and it provides the output according to the characteristics of the system. The open-loop systems are simple, economical, stable, and the changes in the output are not corrected automatically in an open-loop control system. The closed-loop control system is nothing but an open-loop system with a feedback element. The close loop systems are more accurate and less affected by noise. The stepper motors are used in computer peripheral systems, paper drive mechanisms, and automatic control systems. The air conditioners, refrigerators, power systems are examples of control systems. The Voltage stabilizers, Automatic electronic iron, Water tanks with float balls are examples of the closed-loop control system. The control systems are used in electrical systems to control both voltage and current in the electrical system. The aircraft, Automobiles, Helicopters, etc are examples of the system. When a control system is exited with a standard input signal then the steady-state error may be zero or one or infinite. 1). How many types of control systems are there? One Two Three Four Hint 2). The advantages of an open-loop systems are __________ Simple, Economical Easier to construct Stable All of the above Hint 3). What are the disadvantages of a closed-loop control system? Complex, costlier Stability is the main problem Feedback reduces the overall gain of the system All of the above Hint 4). Whenever the control system obeys the linearity and homogeneity then the system is ____________ Time invariant system Linear system Linear time-variant system Linear time-invariant system Hint 5). What are the advantages of a closed-loop control system? Accurate Less effected by noise More effected by noise Both a and b Hint 6). Whenever the control system doesn’t obey the linearity and homogeneity then the system is ____________ Time-invariant system Linear system Non-linear system Linear time-invariant system Hint 7). If output is varying with time then the system is ____________ Time invariant system Linear system Non-linear system Time variant system Hint 8). What are the disadvantages of an open-loop control system? Inaccurate Accurate Easy to construct None of the above Hint 9). If output is not varying with time then the system is ____________ Time invariant system Linear system Non-linear system Time variant system Hint 10). If the control system is both linear and time-variant then the type of system is ____________ Time-invariant system Linear system Linear time-variant system Linear time-invariant system Hint 11). If the control system is both linear and time-invariant then the type of system is ____________ Time-invariant system Linear system Linear time-variant system Linear time-invariant system Hint 12). How many types of feedbacks are there? One Two Three Four Hint 13). The transfer function of negative feedback is expressed as ________ T= G/1+GH T= G/1-GH T= G/1*GH T= G/GH-1 Hint 14). The transfer function of positive feedback is expressed as ________ T= G/1+GH T= G/1-GH T= G/1*GH T= G/GH-1 Hint 15). The transfer function is defined as a ratio of ______________ Laplace transform of output to Laplace transform of the input Laplace transform of output + Laplace transform of the input Laplace transform of output - Laplace transform of the input None of the above Hint 16). The sensitivity is defined as a ___________ Percentage change in transfer function to the percentage change in gain Percentage change in gain to the percentage change in a transfer function Percentage change in transfer function*the percentage change in gain None of the above Hint 17). How many types of mechanical systems are there based on the type of motion? One Two Three Four Hint 18). What are the basic elements in the translational mechanical system? Mass, spring Mass, dashpot Dashpot, spring Mass, spring, and dashpot Hint 19). _________ mechanical systems move along a line Translational Rotational Both a and b None of the above Hint 20). What are the basic elements in the rotational mechanical system? Translational spring Moment of the interior of mass Dashpot All of the above Hint Control System MCQs for Engineers 21). How many analyses do we have to convert any mechanical translational system into an electrical system? One Two Three Four Hint 22). In force voltage analogy the mechanical system input is always considered as _______ Force Velocity Voltage None of the above Hint 23). In force voltage analogy the mechanical system output is in terms of _______ Force Velocity Voltage None of the above Hint 24). _________ mechanical systems will move along an axis Translational Rotational Both a and b None of the above Hint 25). For electrical system in force voltage analogy the input is always considered as _____________ Force Velocity Voltage source None of the above Hint 26). In force voltage analogy the electrical system output is in terms of ______ Force b) c) d) Velocity Voltage source Current through the element Hint 27). In force current analogy the electrical system output is in terms of ______ Force Velocity Voltage through the element Current through the element Hint 28). In torque voltage analogy the mechanical rotational system input is always considered as ____________ Force Velocity Angular velocity Torque Hint 29). Torque equation for mass is expressed as _________ T=J dω/dt T=Bω T=K ∫ωdt None of the above Hint 30). ___________ is a point representing a variable or signal Node Transmittance Branch None of the above Hint 31). In force current analogy the electrical system input is always considered as __________ Current source Velocity Voltage None of the above Hint 32). ______ is a node that contains only outgoing branches Input node Output node Mixed node None of the above Hint 33). How many types of time-domain analyses are there? One Two Three Four Hint 34). The response of the system which varies with time is known as ________ Transient response Steady-state response Both a and b None of the above Hint 35). In torque voltage analogy the mechanical rotational system output is in terms of ____________ Force Velocity Angular velocity Torque Hint 36). Torque equation for dashpot is expressed as ________ T=J dω/dt T=Bω T=K ∫ωdt None of the above Hint 37). _____ is a node that has both outgoing and incoming branches Input node Output node Mixed node None of the above Hint 38). In torque voltage analogy the electrical system is always considered as _________ Voltage Velocity Angular velocity Torque Hint 39). Torque equation for spring is expressed as ________ T=J dω/dt T=Bω T=K ∫ωdt None of the above Hint 40). ________ is a node that contains only incoming branches Input node Output node Mixed node None of the above Hint Control System MCQs for Quiz 41). In torque voltage analogy the electrical system output is in terms of ____________ Force Velocity Angular velocity Current through the element Hint 42). The response of a system that won’t change with time is known as__________ Transient response Steady-state response Both a and b None of the above Hint 43). What are the characteristics of the test signal? Sudden shock Sudden change Constant velocity and acceleration All of the above Hint 44). _____________are the time domain specifications Delay time, rise time Peak time Settling time All of the above Hint 45). The time taken for the response to reach 50% of its final value from the very first time is known as _________ Delay time Peak time Settling time All of the above Hint 46). The time taken for the response to reach 0-100% of its final value from the very first time is known as _________ Rise time Peak time Settling time All of the above Hint 47). How many types of static error constants are there? One Two Three Four Hint 48). The lag-lead compensator produces __________ Phase lag Phase led Both a and b None of the above Hint 49). What are the effects of lag compensator? Stability increases Rise time increases Bandwidth decreases All of the above Hint 50). Compensators are used to __________ Obtain the desired performance of the system Used to stabilize the unstable system Both a and b None of the above Hint 51). The time taken for the response to reach the peak value is called as ________ Rise time Peak time Settling time All of the above Hint 52). What are the effects of lead compensator? Stability increases Rise time decreases Bandwidth increases All of the above Hint 53). How many types of compensators are there based on connections? One Two Three Four Hint 54). How many system analysis methods are there? One Two Three Four Hint 55). _________ is a method which works based on transfer function Polar plot Nyquist rate Root Locus All of the above Hint 56). The transfer-based method is applicable to ____________ system Time variant Non-linear LTI None of the above Hint 57). The state-space method is applicable to _________ Time variant Non-linear Both a and b None of the above Hint 58). How many types of compensators are there? One Two Three Four Hint 59). The dynamic systems are classified into ____________ One Two Three Four Hint 60). In which system the output at any instant of time depends only on past and current inputs? Causal Non-causal Time-invariant None of the above Hint 61). __________ controller produces an output which is derivative of error signal Integral controller Derivative controller Proportional derivative controller None of the above Hint Control System MCQs with Hints 62). __________ controller produces an output which is integral of error signal Integral controller Derivative controller Proportional derivative controller None of the above Hint 63). __________ controller produces an output which is in the combination of the outputs of the proportional and derivative controller Integral controller Derivative controller Proportional derivative controller None of the above Hint 64). ___________ are used to determine the magnitude of CLTF using OLTF M circles N circles Both a and b None of the above Hint 65). ___________ are used to determine the response of a closed-loop system using open-loop transfer function M circles N circles Both a and b None of the above Hint 66). For non-minimum phase system the poles are _________ Left side Right side Either left or right side None of the above Hint 67). How many plots do the bode plot consist of? One Two Three Four Hint 68). In which frequency the maximum magnitude occurs? Resonant frequency Natural frequency Both a and b None of the above Hint 69). __________ is the frequency response technique Bode plot Polar plot Nyquist plot All of the above Hint 70). The systems are categorized into _____________ types based on stability One Two Three Four Hint 71). ____________ technique is used to calculate the stability Root locus, bode plot Nyquist plot, Nicholas chart Routh Hurwitz criterion All of the above Hint 72). When a control system is exited with a standard input signal then the steady-state error is __________ Zero Constant Infinite Zero or one or infinite Hint 73). The state error constants are categorized into _________ One Two Three Four Hint 74). _____________ are the examples of system Aircrafts Automobile Helicopters All of the above Hint 75). The control systems are used in electrical systems to control _____________ in electrical system Voltage Current Both a and b None of the above Hint 76). The example of an open-loop control system is _________ Electric iron Electric fan Water tank All of the above Hint 77). The example of an closed-loop control system is _________ Voltage stabilizers Automatic electronic iron Water tanks with float ball All of the above Hint 78). What are the examples of control systems? Air conditioners Refrigerators Power system All of the above Hint 79). ___________ is used to allow a signal to be used by two or more blocks or summing points Branches Takeoff point Summing point None of the above Hint 80). _________ used for summation of two or more input signals Branches Takeoff point Summing point None of the above Hint Control System MCQs for Exams 81). How many outputs does the summing point have? One Two Three Four Hint 82). Which element indicated the direction of flow of signals in a system? Branches Takeoff point Summing point Arrows Hint 83). The force due to spring is expressed as __________ -Kx Kx –B dx/dt None of the above Hint 84). The force due to damper is expressed as __________ -Kx Kx –B dx/dt None of the above Hint 85). __________ are the basic elements of an electrical system Capacitor Resistor Inductor All of the above Hint 86). _____________ is defined as the flux linkage per unit current Inductance Capacitor Transistor Resistor Hint 87). _________ is defined as a ratio of the charge to the voltage across the capacitor terminals Inductance Capacitor Transistor Resistor Hint 88). The potentiometers are categorized into _________ One Two Three Four Hint 89). The stepper motor is a __________ device Electro-mechanical digital Electro-chemical digital Electro-mechanical analog None of the above Hint 90). The step size of the stepper motor is typically between ___________ 1.5 to 20 deg 1.5 to 30 deg 1.5 to 60 deg 1.5 to 40 deg Hint 91). How many types of stepper motors are there? One Two Three Four Hint 92). How many stator poles does a permanent magnet stepper motor have? One Two Three Four Hint 93). How many rotor poles does a permanent magnet stepper motor have? One Two Three six Hint Read more about Stator Read more about Stepper Motor 94). The full step angle of permanent magnet stepper motor is around _________ 20 deg 30 deg 40deg 50 deg Hint 95). _________ are the applications of stepper motor Automatic control systems Used in computer peripheral systems In paper drive mechanisms All of the above Hint 96). How many types of tacho generators are there? One Two Three six Hint Read more about Generators 97). Tacho generator works on the principle of ___________generator Shunt Series Induction None of the above Hint 98). The techo generator comprises of ___________ One stator winding, rotor Two stator windings, rotor Three stator windings, rotor None of the above Hint 99). How many types of servometers are there? One Two Three six Hint 100). Which servomotor is a DC servo meter? Armature controlled Field controlled Both a and b None of the above Hint 101). Error detector is available in _________ systems Open-loop Closed-loop Both a and b None of the above Hint 102). The feedback is available in ___________ control system Open-loop Closed-loop Both a and b None of the above Hint 103). In which control system the sensitivity is less? Open-loop Closed-loop Both a and b None of the above Hint 104). Which one is an example of servomechanism? Missile launcher Speed governor Frequency regulator None of the above Hint 105). Which one is an example for the regulator? Machine tool position control Roll stabilization in ships Missile launcher None of the above Hint 106). How many types of hydraulic output devices are there? One Two Three Four Hint 107). The transfer function of an integrator is expressed as _______ T=1/S T=1/S+1 T=1/S-1 T=1/S+a Hint 108). The transfer function of an differentiator is expressed as _______ T=S T=1/S+1 T=1/S-1 T=1/S+a Hint 109). The transfer function of a first-order system is expressed as _______ T=S T=1/S+1 T=1/S-1 T=1/S+a Hint 110). ________ is an example for state variable Current flowing through the inductor Voltage across a capacitor Both a and b None of the above Hint 111). Based on the gain and phase margins the control system is stable when _________ Gain margin<1, the phase margin is positive Gain margin>1, the phase margin is positive Gain margin<1, the phase margin is Negative None of the above Hint 112). Based on the gain and phase margins the control system is marginally stable when _________ Gain margin<1, the phase margin is positive Gain margin>1, the phase margin is positive Gain margin=1, the phase margin is zero degrees None of the above Hint 113). Based on the gain and phase margins the control system is unstable when _________ Gain margin<1, the phase margin is negative Gain margin>1, the phase margin is positive Gain margin=1, the phase margin is zero degrees None of the above Hint 114). Based on the phase and gain cross over frequencies the control system is stable when __________ Phase cross over frequency>gain cross over frequency Phase cross over frequency<gain cross over frequency Phase cross over frequency=gain cross over frequency None of the above Hint 115). Based on the phase and gain cross over frequencies the control system is marginally stable when __________ Phase cross over frequency>gain cross over frequency Phase cross over frequency<gain cross over frequency Phase cross over frequency=gain cross over frequency None of the above Hint 116). Based on the phase and gain cross over frequencies the control system is unstable when __________ Phase cross over frequency>gain cross over frequency Phase cross over frequency<gain cross over frequency Phase cross over frequency=gain cross over frequency None of the above Hint 117). What are the specifications of the frequency domain? Resonant peak Resonant frequency Bandwidth All of the above Hint 118). How many types of connections are possible between the blocks? One Two Three Four Hint 119). How many types of controllers are there? One Two Three Four Hint 120). What are the functions of automatic control? Measurement Comparison, correction Computation All of the above Hint 121). _______ is an example for natural control system Universe Vehicles Helicopters None of the above Hint 122). ________ is an example for manmade control system Universe Vehicles Human body None of the above Hint 123). ________ is an example for automatic control system Human body temperature control Water level control Vehicles None of the above Hint 124). ________ is an example for manual control system Human body temperature control Water level control Vehicles None of the above Hint 125). The close loop control systems are categorized into ______ One Two Three Four Hint 126). The non-linear closed-loop control systems are again categorized into ______ One Two Three Four Hint 127). The open-loop and closed-loop control systems are ________ Natural control systems Manmade control systems Both a and b None of the above Hint 128). The AC servo system has __________ Low efficiency Low power output Fewer stability problems All of the above Hint 129). The DC servo system has __________ High efficiency High power output More stability problems All of the above Hint 130). Which servo system has non-linear characteristics? AC servo system DC servo system Both a and b None of the above Hint Control System Important MCQs 131). The linear closed-loop control systems are again categorized into ______ One Two Three Four Hint 132). Which control system is a non-feedback control system? Open-loop Closed-loop Both a and b None of the above Hint 133). How many types of transfer function model analyses are there? One Two Three Four Hint 134). Which one is a response analysis of the transfer function model? Time-domain analysis Frequency domain analysis Both a and b None of the above Hint 135). Which one is a stability analysis of the transfer function model? Function model Nyquist Bode plot Gain and phase margins All of the above Hint 136). How many types of cascade connections are there? One Two Three Four Hint 137). ________ are the applications of DC servomotor Machine tools Process controllers Robotics All of the above Hint 138). How many types of actuators are there? One Two Three Four Hint 139). The fluid used in pneumatic system is ________ Air Oil Water None of the above Hint 140). The fluid used in hydraulic system is ________ Air Oil Water None of the above Hint 141). Which system is explosion-proof and fire-proof? Pneumatic Hydraulic Both a and b None of the above Hint 142). The non-linearities are categorized into _________ One Two Three Four Hint 143). The electric actuators are categorized into _________ One Two Three Four Hint 144). The stepper motors are of _______ One Two Three Four Hint 145). _________ sensor is used in home heating systems Temperature sensor Thermostat sensor Float sensor None of the above Hint 146). _________ sensor is used in automotive engine Temperature sensor Thermostat sensor Float sensor None of the above Hint Read more about Sensors 147). _________ sensor is used in toilet tank water level Temperature sensor Thermostat sensor Float sensor None of the above Hint 148). The multimedia contains _______ Voice, music Video, animation Graphics All of the above Hint 149). The regenerative feedback is also known as ______ Positive feedback Negative feedback Both a and b None of the above Hint 150). Which magnet is used in DC motor construction? Permanent magnet Plastics Electromagnet None of the above Hint 151). The rotors has _________ No windings No brushes No commutators All of the above Hint 152). Which valve restricts the airflow? Throttle valve Shuttle valve Both a and b None of the above Hint 153). For a unit step input the steady-state error is _______ 1/1+KP 1/1-KP 1/KP None of the above Hint 154). The control systems invented by ______ James Clerk Maxwell Charles Denis Papin None of the above Hint 155). In control systems the controller output is given to __________ Amplifier Sensor Final control element None of the above Hint 156). ____________ signal is an input to the controller Error Servo Sensed None of the above Hint 157). The low power AC motors and DC motors are called as ________ Tachogenerators AC and DC generators Servomotors None of the above Hint 158). The lubricator is a _____ element in the pneumatic circuit First Second Third Last Hint 159). The peak overshoot and damping ratio are measures of ____________ Speed of response Steady-state error Both a and b None of the above Hint 160). In a closed-loop control system, the peak percentage overshoot is around _______ 20% 30% 40% 16.3% Hint Control Systems Important MCQs for Students 161). Hydraulic controller requires __________ operation High speed High torque Both a and b None of the above Hint 162). Pneumatic controller requires __________ for its operation Air Gas fuel Both a and b None of the above Hint Read more about Temperature Controller 163). The electronic controller operation is __________ Flexible Not flexible Requires high torque operation None of the above Hint 164). For minimum phase system poles lies on __________ and zeros lies on _______plane Poles lies on left Poles lies on the right Zeros lies on left Both a and c Hint 165). For non minimum phase system poles lies on __________ and zeros lies on _______plane Poles lies on left Zeros lies on the right Zeros lies on left Both a and b Hint 166). The minimum phase system and all-pass system constitute _______ Maximum phase system Non-maximum phase system Minimum phase system Non-minimum phase system Hint 167). The radius size for Nyquist contour is _______ One Zero Infinite None of the above Hint 168). _________ margin measures relative stability Phase Gain Both a and b None of the above Hint 169). Gain margin is __________ in second-order system One Zero Infinite None of the above Hint 170). The measure of relative stability is __________ in frequency domain Phase margin Resonant peak Both a and b None of the above Hint 171). The speed of response in the time domain is measure in terms of _______ Settling and rise time Natural frequency Both a and b None of the above Hint 172). The speed of response in the frequency domain is measure in terms of _______ Settling and rise time Resonant peak Bandwidth Both b and c Hint 173). AC servomotor is a __________ induction motor Single phase Double phase Triple phase None of the above Hint 174). The raster images also called as _______ images Clipart Vector Bitmap None of the above Hint 175). In a closed-loop system the relation between output response and input signal is ________ Linear Parabolic Non-linear None of the above Hint Time is Up! Time's up