Explore topic-wise MCQs in BITSAT.

This section includes 159 Mcqs, each offering curated multiple-choice questions to sharpen your BITSAT knowledge and support exam preparation. Choose a topic below to get started.

51.

In the circuit shown, the diodes are ideal, the inductance is small and I0 ≠ 0 . Which one of the following statements is true?

A. D1 conducts for greater than 180° and D2 conducts for greater than 180°
B. D2 conducts for more than 180° and D1 conducts for 180°
C. D1 conducts for 180° and D2conducts for 180°
D. D1 conducts for more than 180° and D2 conducts for 180°
Answer» B. D2 conducts for more than 180° and D1 conducts for 180°
Discussion
52.

78XX series of voltage regulator ICs are available in ______

A. 2 pin IC package
B. 3 pin IC package
C. 4 pin IC package
D. 8 pin IC package
Answer» C. 4 pin IC package
Discussion
53.

Match List-I with List-II:List-IList-IIa)Ripple factori)\(\frac{1}{(3√2)}\frac {R_L}{ωL}\)b)Ripple factor of L-section filterii)\(\sqrt{(\frac{I_{rms}}{I_dc })^2-1}\)c)Ripple factor of an inductor filteriii)\(\frac{√2}{3} \frac{ 1}{2ωC}\frac{ 1}{2ωL}\)d)Percentage of regulationiv)\(\frac{R_s}{R_L} ×100%\)

A. a-i; b-ii; c-iv; d-iii
B. a-ii; b-iii; c-i; d-iv
C. a-iii; b-iv; c-ii; d-i
D. a-iv; b-i; c-iii; d-ii
Answer» C. a-iii; b-iv; c-ii; d-i
Discussion
54.

A Zener regulator has an input voltage varying between 20 V and 30 V. The desired regulated voltage is 12 V, while the load varies between 140 Ω and 10 kΩ. The minimum resistance in series with the unregulated source and Zener diode would be

A. 3.3 Ω
B. 6.6 Ω
C. 36.6 Ω
D. 93.3 Ω
Answer» E.
Discussion
55.

50 Hz, 230 V is applied to a full-wave rectifier. Its output frequency is:

A. 50 Hz
B. 100 Hz
C. 25 Hz
D. 50 rad / s
Answer» C. 25 Hz
Discussion
56.

In the circuit shown, the breakdown voltage and the maximum current of the Zener diode are 20 V and 60 mA, respectively. The values of R1 and RL are 200 Ω and 1 kΩ, respectively. What is the range of Vi that will maintain the Zener diode in the ‘on’ state?

A. 22 V to 34 V
B. 24 V to 36 V
C. 18 V to 24 V
D. 20 V to 28 V
Answer» C. 18 V to 24 V
Discussion
57.

A Schottky diode is a

A. Both majority and minority carrier diode
B. Majority carrier device
C. Minority carrier device
D. Fast recovery diode
Answer» C. Minority carrier device
Discussion
58.

Diodes are used to compensate which of the following transistor circuit parameters?1. Ico2. VBE3. β

A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer» B. 2 and 3 only
Discussion
59.

A full-wave rectifier connected to the output terminals of the mains transformer produces an RMS voltage of 18 V across the secondary. The no-load voltage across the secondary of the transformer is

A. 1.62 V
B. 16.2 V
C. 61.2 V
D. 6.12 V
Answer» C. 61.2 V
Discussion
60.

A Zener diode voltage regulator has load requirement of 16 V and 2 Amp.The diode's minimum current requirement is 2.5 A. The minimum voltage at input is 29 V. What will be the maximum efficiency of the circuit?

A. 44.13%
B. 23.99%
C. 78%
D. 88.90%
Answer» C. 78%
Discussion
61.

Current flow in a semiconductor depends on the phenomenon of

A. drift
B. diffusion
C. recombination
D. All of these
Answer» E.
Discussion
62.

A bridge rectifier uses a 9 V a.c. input voltage. The diodes are ideal. What is the d.c. output voltage?

A. 12.726 V
B. -12.726 V
C. 9 V
D. 8.1 V
Answer» E.
Discussion
63.

If Vm is the peak value of an applied voltage in a half wave rectifier with a large capacitor across the load, then the peak inverse voltage will be

A. 0.5 V­m
B. Vm
C. 1.5 Vm
D. 2.0 Vm
Answer» E.
Discussion
64.

In the given circuit, Vbe = 0.7 V, Vx = 5.3 V, β = 100. V0 is

A. 5 V
B. 10 V
C. 15 V
D. 20 V
Answer» C. 15 V
Discussion
65.

Calculate the maximum value of Rs in the given circuit to give 12 V regulated output from an unregulated supply of 28 V for a maximum load current of 150 mA (Zener voltage is 12 V and knee current of Zener diode is 10 mA)

A. 110 Ω
B. 106.67 Ω
C. 120 Ω
D. 100 Ω
Answer» E.
Discussion
66.

Calculate the reverse resistance of a Si diode when the reverse voltage is 50 V and the current is 100 nA.

A. 500 MΩ
B. 100 MΩ
C. 50 MΩ
D. 600 MΩ
Answer» B. 100 MΩ
Discussion
67.

A zener diode is generally operated

A. in a forward biased mode
B. in a reverse biased mode
C. with a very large value of reverse bias
D. all of the above
Answer» C. with a very large value of reverse bias
Discussion
68.

Peak inverse voltage of diode used in half-wave rectifier is

A. 2Vm
B. Vm
C. Vm/2
D. Vm/3
Answer» C. Vm/2
Discussion
69.

Determine the supply current in the given network. Take the voltage drop during the forward biased condition is 0.3 V.

A. \(\frac{11.7}{14} A\)
B. \(\frac{11.4}{6} A\)
C. \(\frac{11.7}{10} A\)
D. \(\frac{11.7}{6 }A\)
Answer» E.
Discussion
70.

Compared to an ordinary semiconductor diode, a Schottky diode has

A. higher reverse saturation current and zero cut-in voltage
B. higher reverse saturation current and higher cut-in voltage
C. higher reverse saturation current and lower cut-in voltage
D. lower reverse saturation current and lower cut-in voltage
Answer» D. lower reverse saturation current and lower cut-in voltage
Discussion
71.

A SCR is a ______ switch.

A. unidirectional
B. bidirectional
C. no-direction
D. none of the above
Answer» B. bidirectional
Discussion
72.

A diode under forward biased condition _______.

A. Blocks current
B. Drops a large voltage
C. Has a high resistance
D. Conducts current
Answer» E.
Discussion
73.

A full-wave rectifier using centre tapped transformer and a bridge rectifier use similar diodes and have equal no load output voltage. Under equal load conditions:

A. Output of bridge rectifier will be less than the of the other
B. Output of bridge rectifier will be more than that of the other
C. Output voltage of both will be exactly equal
D. Output voltage of anyone may be more than that of other
Answer» B. Output of bridge rectifier will be more than that of the other
Discussion
74.

In the full-wave rectifier circuit shown in the figure, the diodes that conduct when the positive half-wave of AC signal applied are:

A. D1, D2
B. D3, D4
C. D2, D3
D. D4, D1
Answer» B. D3, D4
Discussion
75.

A combination of two diodes connected in parallel when compared to a single diode can withstand

A. twice the value of peak inverse voltage
B. twice the value of maximum forward current
C. a large leakage current
D. twice the value of cut-in voltage
Answer» C. a large leakage current
Discussion
76.

A 40 V dc supply is connected across the network comprising of Zener and silicon diodes as shown. The regulated voltages V01, V02 and source current Is are

A. 2.4 V, 5.1 V and 21.7 mA
B. 3 V, 6 V and 22.7 mA
C. 3.3 V, 9.3 V and 20.5 mA
D. 4 V, 10 V and 20 mA
Answer» E.
Discussion
77.

A device having characteristics very close to that of an ideal voltage source is _____.

A. Vacuum diode
B. Zener diode
C. Transistor
D. FET
Answer» C. Transistor
Discussion
78.

A crystal diode that has an internal resistance of 20 Ω is used for rectification. If the supply voltage is 50 sin ωt and the load resistance is 800 Ω, then find the rms value of the load current.

A. 61 mA
B. 30.5 mA
C. 19.4 mA
D. 38.8 mA
Answer» C. 19.4 mA
Discussion
79.

A silicon diode has a forward voltage drop of 1.2 V for a forward DC current of 100 mA. It has a reverse current of 1 μA for a reverse voltage of 10 V. Calculate reverse resistance of the diode.

A. 25 MΩ
B. 20 MΩ
C. 5 MΩ
D. 10 MΩ
Answer» E.
Discussion
80.

A full-wave rectifier uses two diodes, the internal resistance of each diode is 20 Ω constant. The transformer r.m.s secondary voltage from the center tap each end of the secondary is 50 V and load resistance is 980 Ω. Find the maximum load current.

A. 70.7 mA
B. 0.7 mA
C. 3.5 mA
D. 7.07 mA
Answer» B. 0.7 mA
Discussion
81.

A diode can be used as frequency multiplier because of:

A. Charge carrier concentration
B. Junction capacitance
C. Non linearity
D. Avalanche voltage
Answer» D. Avalanche voltage
Discussion
82.

A forward potential of 7 V is applied across a network consisting a schottky diode with 1 KΩ resistor in series. The current through the diode is _____

A. 10 mA
B. 7.3 mA
C. 6.8 mA
D. 0 mA
Answer» D. 0 mA
Discussion
83.

In the figure, assume that the forward voltage drops of the PN diode D1 and Schottky diode D2 are 0.7 V and 0.3 V, respectively. If ON denotes conducting state of the diode and OFF denotes a non-conducting state of the diode, then in the circuit.

A. Both D1 and D2 are ON
B. D1 is ON and D2 is OFF
C. Both D1 and D2 are OFF
D. D1 is OFF and D2 is ON
Answer» E.
Discussion
84.

In a Zener diode shunt voltage regulator, the diode regulates so long as it is kept in a/an _______ condition.

A. reverse-biased
B. unloaded
C. forward-biased
D. loaded
Answer» B. unloaded
Discussion
85.

PIV of a non conducting diode in a bridge rectifier is

A. Twice the peak value of a.c. input
B. Half the peak value of a.c. input
C. Four times the peak value of a.c. input
D. Peak value of a.c. input
Answer» E.
Discussion
86.

A capacitor may be needed in a discrete voltage regulator to prevent

A. Negative feedback
B. Excessive load current
C. Oscillations
D. Current sensing
Answer» D. Current sensing
Discussion
87.

Current I for the circuit shown will be

A. 3 mA
B. 2.81 mA
C. 6.16 mA
D. 10 mA
Answer» B. 2.81 mA
Discussion
88.

A three-phase full-wave rectifier with resistive load has a ripple factor

A. 0.482
B. 1
C. 0.055
D. 0.5
Answer» D. 0.5
Discussion
89.

In the circuit shown, diodes D1, D2 and D3 are ideal, and the inputs E1, E2 and E3 are “0 V” for logic ‘0’ and “10 V” for logic ‘1’. What logic gate does the circuit represent?

A. 3-input OR gate
B. 3-input NOR gate
C. 3-input AND gate
D. 3-input XOR gate
Answer» D. 3-input XOR gate
Discussion
90.

In this circuit, V is a sinusoid input with freq. f, current i contains:

A. Only f
B. All harmonics of f
C. Only even harmonics of f
D. Only odd harmonics of f
Answer» C. Only even harmonics of f
Discussion
91.

For the circuit shown above, using ideal diode, the values of voltage and current are

A. -3 V and 0.6 mA
B. 3 V and 0.5 mA
C. 3 V and 0.6 mA
D. 3 V and 0.0 mA
Answer» B. 3 V and 0.5 mA
Discussion
92.

In a photovoltaic system, there is a thermally generated small reverse saturation current which flows even in the absence of light, called

A. Photon current
B. Diode current
C. Leakage current
D. Dark current
Answer» E.
Discussion
93.

IC 7805 is a ____ voltage regulator.

A. 15 V
B. 8 V
C. 6 V
D. 5 V
Answer» E.
Discussion
94.

In a LC filter, the ripple factor,

A. Increases with the load current
B. increases with the load resistance
C. remains constant with the load current
D. has the lowest value
Answer» D. has the lowest value
Discussion
95.

If the series resistance increases in an unloaded Zener regulator, the Zener current

A. Decreases
B. Stays the same
C. Increases
D. Equals the voltage divided by the resistance
Answer» B. Stays the same
Discussion
96.

Determine the diode current assuming it to be ideal.

A. 2 mA
B. 6 mA
C. 4 mA
D. 8 mA
Answer» D. 8 mA
Discussion
97.

A full-wave rectifier with a center-tapped transformer supplies a DC of 100 mA to a load resistance of 20 Ω. The secondary resistance of the transformer is 1 Ω. Each diode has a forward resistance of 0.5 Ω. What are RMS values of signal voltage across each half of the secondary as well as dc power supplied to the load?

A. 2.39 V and 0.2 Watt
B. 23.9 V and 2 Watts
C. 0.239 V and 20 Watts
D. 2.39 V and 2 Watts
Answer» B. 23.9 V and 2 Watts
Discussion
98.

A 700 mW maximum power dissipation diode at 25°C has 5 mW/°C de-rating factor. If the forward voltage drop remains constant at 0.7 V, the maximum forward current at 65°C is

A. 700 mA
B. 714 mA
C. 1 A
D. 1 mA
Answer» C. 1 A
Discussion
99.

For a full wave bridge rectifier supplied with 50 Hz ac, the lowest ripple frequency is

A. 50 Hz
B. 100 Hz
C. 5 Hz
D. 10 Hz
Answer» C. 5 Hz
Discussion
100.

A center tap full rectifier consists of:

A. one diode
B. three diodes
C. two diodes
D. four diodes
Answer» D. four diodes
Discussion