Multivibrator Question & Answers August 4, 2021 By WatElectronics This article lists 100 Multivibrator MCQs for engineering students. All the Multivibrator Questions & Answers given below includes solution and link wherever possible to the relevant topic. A sequential logic circuit utilized in building up complex circuitry can be a Counter, Latch, and Memories. These circuits must be provided with a timing or clock signal to make them function sequentially. This type of Single Pulse Generator circuit is known as a Multivibrator. Multivibrators are available in three types like astable, monostable, and bistable. The astable multivibrator has no stable states, so it switches continually from one condition to the other. So, it works like a relaxation oscillator. In a monostable multivibrator, one of the states is stable whereas the other state is not stable. As the name suggests, a bistable multivibrator includes two stable states. Here, a separate trigger signal is necessary from one stable state to another stable state for the transition. The applications of multivibrators mainly include; these can be used as saw tooth generators, frequency generators, pulse, and wave generators, used in tv and radar circuits, etc. 1). Multivibrators are also referred to as ______. Linear oscillators Non-linear oscillators Function generators b and c None Hint 2). Which feedback does a multivibrator have? Positive and Negative Only Negative Regenerative Degenerative None Hint 3). What are the types of Multivibrators? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator All the above None Hint 4). Astable Multivibrators has ________ Stable states. Zero One Two Three None Hint 5). Which multivibrators consist of One Stable state? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Tristable Multivibrator None Hint 6). What type of Multivibrator can produce only one Single pulse? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Data insufficient None Hint 7). How many states does a Bistable Multivibrator possess? Zero One Two Three None Hint 8). What do you mean by Quasi stable? Permanent stable Temporary stable Steady state Can’t say None Hint 9). What are the elements used for coupling in Bistable Multivibrators? Resistors Capacitors Inductors Diodes None Hint 10). What type of multivibrator needs triggering for Reverse transition? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Pulse Generator None Hint 11). Astable multivibrators can function as ______________. Linear oscillators Relaxation oscillators Non-Relaxation oscillators a & c None Hint 12). Which Multivibrator is known as Flip-flop Multivibrator? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Pulse Generator None Hint 13). What are the other names of Bistable multivibrators? Flip-flop Binary Trigger circuit All mentioned earlier None Hint 14). Monostable multivibrator is also known as ___________. One shot Monoflop Flip-flop Both a and b None Hint 15). Why the Monostable Multivibrator referred to as Delay circuit? Transition time is predetermined No need of transition Transition is slow Data insufficient None Hint 16). Bistable Multivibrators is known as _________. One shot Mono flop Relaxation Oscillator Binary None Hint 17). How do Multivibrators differ from Oscillators? Produces one waveform as outcome Generates rectangular, square, and pulse waves as outcomes Produces sine wave as output Same None Hint 18). Why a Flip-flop Multivibrator is termed as Two-shot Multivibrator? One state is stable Two states are stable Three states are stable Four states are stable None Hint 19). How many trigger pulses required for Bistable multivibrators? One Two Three Four None Hint 20). Which of these multivibrator produces square wave as the outcome? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Triggered Oscillator None Hint 21). Duty cycle of an Astable multivibrator is ________. 30% 50% 70% 100% None Hint 22). What kind of multivibrators have equal time for a capacitor to charge and discharge? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator Triggered Oscillator None Hint 23). How many stages of amplifier present in Astable Multivibrator? One Two Three Four None Hint 24). Which is the feedback present in Astable multivibrators? Positive and Negative Only Negative Only Positive Degenerative None Hint 25). Which of the below circuit has a Quasi stable state? Bistable multivibrator Monostable multivibrator Tristable multivibrator Tetra stable multivibrator None Hint Multivibrators Important Questions for Interviews 26). What does a symmetrically coupled collector circuit consists of? Two transistors identical Resistors and Capacitors Both a and b Transformer None Hint 27). What happens to the signal when passed through Common-emitter amplifier’s first stage? Strength is reduced Decrease in frequency Reversed phase Doesn’t change None Hint 28). Multivibrators output is collected from ___________ of any transistor. Base Emitter Collector Drain None Hint 29). How the transistors Q1 and Q2 alternates in the multivibrator circuit? Q1 On, Q2 Off Q1 Off, Q2 Off Q1 On, Q2 On Can’t say None Hint 30). Total time period of the Square wave is ________. 0.69 RC 1.38 RC 1.48 RC 1.68 RC None Hint 31). How the frequency can be determined for the oscillations? Reciprocate of Time period 1/ 1.38RC 1/0.69RC Both a and b None Hint 32). Which is known as Free-running Multivibrator? Astable multivibrator Monostable multivibrator Bistable multivibrator Both a and b None Hint 33). How frequency at the output can be varied in Astable multivibrator circuit? Changing the resistor value Changing the capacitor value Both a and b Changing the transistors None Hint 34). What is the main application of a Monostable multivibrator? Oscillators Timers Flip-flops Binary None Hint 35). What happens to the Monostable circuit when it is triggered externally? Jump to Stable state Jump to Quasi-stable state Doesn’t change Oscillates frequently None Hint 36). Monostable circuit from state of Quasi-stable will return to Stable by _________. With an External trigger Due to Predefined time interval Without any External trigger b and c None Hint 37). On what factor the time interval in the Multivibrator circuit depend? External trigger Resistor value Capacitor value b and c None Hint 38). What happens to the Monostable circuit if it is not triggered externally? Both transistors are at Cut-off Both transistors in Saturation One transistor is at Cut-off, other is at saturation Both transistors are Active None Hint 39). What are the applications of a Monostable circuit? Timers Delay circuits Gated circuits All mentioned earlier None Hint 40). The cycle to charge a capacitor is __________ than a cycle of discharge in Astable multivibrator. Faster Slower Lesser Compressed None Hint 41). Which of these multivibrators are preferred for lower clock frequencies? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 42). What kind of Multivibrator have two networks of RC? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 43). Monostable multivibrator consists of _________. Two transistors RC and Resistive networks Absent load capacitor a, b and c None Hint 44). Which multivibrators have only Resistive coupling? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 45). Which multivibrators need external triggering to operate? Bistable multivibrator Monostable multivibrator Astable multivibrator a & b None Hint 46). What does a Astable multivibrator comprise of? Two transistors Feedback network Delay capacitors a, b and c None Hint 47). How many capacitors present in Astable circuit? Two Three Four Five None Hint 48). What kind of multivibrator preferred in Flash lights? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 49). On what factors the output wave generated is dependent on? Two transistors Feedback network Delay capacitors Frequency None Hint 50). Which is the most commonly preferred circuit of Multivibrators? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint Multivibrator Question & Answers 51). What can improve the switching capability in Bistable multivibrators? Resistors Capacitors Transistors Feedback None Hint Read More About Flip-Flops 52).What reduces the time of transition in Bistable multivibrator? Resistors Capacitors Transistors Feedback None Hint 53). Commutating capacitors are also referred to as ________ capacitors. Slow-Down Speed-Up Transition Slow None Hint 54). What multivibrator is chosen for counting applications? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 55). Which is the costliest multivibrator? Astable multivibrator Monostable multivibrator Bistable multivibrator Can’t say None Hint 56). What is the disadvantage of Bistable circuit? Triggering is must Store previous outcome Design is simple Direct coupling None Hint 57). Frequency divider application uses _________. Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 58). Which of the multivibrator are known for repairing damaged pulses? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 59). Which of the multivibrator chosen to function as Linear Ramp Generator? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 60). Which state the Bistable circuit will be without trigger? Low High Reset Quasi None Hint 61). What happens to the Bistable circuit at High state when the Reset is applied? Changes from Low to High Changes from High to Low Switches continuously Remains same None Hint 62). What are the multivibrators constructed using 555 Timer? Astable Multivibrator Monostable Multivibrator Bistable Multivibrator a, b and c None Hint 63). How many comparators are present in Timer 555? Five Four Three Two None Hint 64). Which is the most simple circuit constructed using Timer 555? Bistable multivibrator Monostable multivibrator Astable multivibrator Tetra stable multivibrator None Hint 65). In which applications 555 timer can be used? Multivibrators Pulse width modulation Oscillators a, b and c None Hint 66). What are the components connected to timer 555 to function it as Astable multivibrator? Two Resistors Capacitor a and b Diode None Hint 67). How Pulse position modulation is achieved using 555 Timer? Operating at Astable mode Operating at Monostable mode Operating as Astable and Monostable modes Operating at Bistable mode None Hint 68). Why 555 Integrated circuit used in the multivibrators? Easily available Complex in design Only Astable circuit is designed Only Bistable circuit can be designed None Hint 69). To achieve PPM the first 555 IC will be operated in __________ mode. Astable Bistable Monostable Astable and Monostable None Hint 70). To which pin modulation signal is applied in 555 Timer? Pin 5 Pin 4 Pin 3 Pin 2 None Hint 71). From which of the pins the output of PPM can be collected? Pin 5 Pin 4 Pin 3 Pin 2 None Hint 72). How the time constant of a capacitor to charge and discharge related in Astable 555 circuit? Time constant of charging > Discharging Time constant of charging < Discharging Time constant of charging = Discharging Time constant of charging & Discharging are same None Hint 73). High output stays __________ in comparison with the Low Output in Astable circuit. Shorter Longer Equivalent Symmetric None Hint 74). What is the characteristic of the output obtained by Astable circuit? Symmetric Asymmetric Similar Proportionate None Hint 75). What do you define as TON / T? Time constant Charging time Duty cycle Discharging time None Hint Multivibrators MCQs with Answers 76). T in the duty cycle stands for _______. One cycle Time interval Multiple cycles Time interval Charging Time interval Discharging Time interval None Hint 77). How can you define Duty cycle? Relation amid High and Low output Relation between Time constants Relation between Resistors Relation between capacitors None Hint 78). How the charging time TC calculated in 555 Astable circuit? 0.6938*C (R1+ R2) 0.693*C (R1+ R2) 0.7938*C(R1+ R2) 0.693*C(R1) None Hint 79). What is the discharge timing of an Astable circuit of 555? 0.6938*C (R1+ R2) 0.693*C (R2) 0.7938*C (R1+ R2) 0.693*C(R1) None Hint 80). What is the component connected to 555 circuit to obtain Frequency Modulation? High pass filter Low pass filter Band pass filter Band reject filter None Hint 81). Which device connected Astable circuit to achieve FM? FET MOSFET UJT Diode None Hint 82). Astable circuit to achieve FM’s Modulation signal voltage and time period are ______. Directly proportional Inversely proportional Same Asymmetric None Hint 83). Can an Astable multivibrator able to generate pulse of various widths? Yes No Impossible Can’t say None Hint 84). What sets the voltage to high in Monostable circuit? Rising edge Falling edge Positive edge Leading edge None Hint 85). What are the components necessary to make 555 as Monostable circuit? Resistor Capacitor Diode a & b None Hint 86). In Linear ramp generation circuit what is used as constant source of current? Current mirror Diode Transistor (PNP) All as mentioned earlier None Hint 87). What circuit is used as a missing pulse detector? Astable Bistable Monostable Astable and Monostable None Hint 88). What components can make Monostable circuit as Missing pulse detector? Resistor Capacitor Transistor (PNP) b & c None Hint 89). What type of wave is generated by Free-running Multivibrators? Triangular Square Saw tooth Sine None Hint 90). Which circuit is referred to as Pulse Generator Circuit? Amplifiers Rectifiers Multivibrator Frequency divider None Hint 91). Which multivibrators are used as Memory elements? Astable Bistable Monostable Astable and Monostable None Hint 92). Discharge time of a capacitor in a Monostable circuit is termed as _________ time. Saturation Static Dynamic Recovery None Hint 93). Which element in Monostable circuit of CMOS prevent rising of input signal? Diode Transistor Inductor Capacitor None Hint 94). The output finite resistance in the Astable circuit of CMOS can be ______. Finite Infinite Negotiable Certain Ohms None Hint 95). Which type of Multivibrator generates Clock pulse? Astable Bistable Monostable Astable and Monostable None Hint 96). Bistable multivibrator is a _______. Oscillator Schmitt trigger Comparator Amplifier None Hint 97). What is the outcome of the Schmitt trigger? Sine wave Triangular wave Saw-tooth wave Square wave None Hint 98). What are the components required in building Op-amp based Astable circuit? Op-amp Resistors & Capacitor Diode a, b and c None Hint 99). A Monostable circuit with resistance (R) 100 Kilo ohms with a Time delay (T) of 1000 milliseconds. Find the Capacitor value? 1.23 micro farads 7.6 micro farads 9.09 micro farads 10.01 micro farads None Hint 100). A Monostable circuit with resistance (R) as 100 kilo ohms and capacitor (C) as 10 micro farads calculate the Time delay? 100 milli seconds 1000 milli seconds 1100 milli seconds 1200 milli seconds None Hint Time's up
