GATE

Practice Sheet 01
ECE and EE
Analog Electronics
Diode Circuits

Q1 The diode in the circuit given below has Von =

0.7 V, but is ideal otherwise. The current (in
mA) in the
4 kΩ resistor is ______.

Q2 Value of current I and voltage V in given ideal

diode circuit is Q4 The value I0 and V0 in given circuit is___

Assume diode to be ideal.

(A) 0.5mA , 0V
(B) 0 mA , –1.66V
(C) 0 mA , 0 V
(D) 0.5 mA, –1.66 V

Q5 What is the output voltage Vo for the circuit

(A) 1mA , –10V shown below assuming an ideal diode?

(B) 1 mA, 0 V
(C) 0 mA, 3.33V
(D) 0 mA, –10V

Q3 In the following figure cut-in voltage for Si

diode = 0.7 V and Cut-in voltage for Ge diode =
0.3 V, then output voltage Vo is_____.

(A) (B)

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(C) (D)

Q6 Let the cut in voltage 𝑽𝜸 = 0.7 V for each diode

in the circuit shown below.

Q10 Diodes are ideal, value of voltage V and

current I is_________
(A) 2.8 V (B) –2.8 V
(C) –3.6 V (D) 3.6 V

Q7 The circuit inside the box in figure shown

below contains only resistor and diodes. The
terminal voltage v0 is connected to some point
in the circuit inside the box. The largest and
smallest possible value of v0 most nearly is
(A) 0A, 0V (B) 1A, 1V
respectively:
(C) 2A, 2V (D) 3A, 3V

Q11 Value of Vo in given circuit is ___(assume

diodes are idea)l

(A) 15V, -9V (B) 10V, -9V

(C) 15V, -8V (D) 12V, -9V

Q8 If Vi = 10 sin t volt, then Duty cycle of diode D1

and D2 is_________

Q12 Draw output waveform

(A) D1Off, D2Off (B) D1Off, D2On

(C) D1On, D2Off (D) D1Off, D2On

Q9 Diodes are ideal, value of voltage V is

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Q13 For the circuit shown below each diode has Vγ load RL is _______ (round off to one decimal
= 0.7 V and Rf = 0. Both diodes will be ON if place)

Q17 A non-ideal diode is biased with a voltage of

(A) VS> 1.085 V -0.03 V, and a diode current of I1 is measured.
(B) VS> 2 V The thermal voltage is 26 mV and the ideality
(C) VS> 3.9 V factor for the diode is 15/13. The voltage, in V,
(D) VS> 4.55 V at which the measured current increases to
1.5I1 is closest to:
Q14 Vi = 5sin(wt) volt
(A) –4.50 (B) –0.09
Draw V0 versus Vi
(C) –0.02 (D) –1.50

Q18 Consider the diode circuit shown below. The

diode, D, obeys the current-voltage

characteristic , where

n > 1, VT > 0, VD is the voltage across the diode

and ID is the current through it. The circuit is
biased so that voltage, V > 0 and current, I < 0.
If you had to design this circuit to transfer
(A) D1ON, D2ON (B) D1Off, D2Off
maximum power from the current source (I1)
(C) D1ON, D2Off (D) D1Off, D2ON
to a resistive load (not shown) at the output,
Q15 For the circuit shown in the figure, assume what values of r1 and R2 would you choose?
that, diodes are ideal, average value of V1 and
V2 is____

(A) Large R1and large R2.

(B) Small R1and small R2.
(C) Large R1and small R2.
Q16 A Zener diode is used as a 4 V voltage (D) Small R1and large R2.
regulator in the circuit shown. Given that the
diode requires a minimum current of 4 mA for Q19 The PIV rating of the diodes used in power

voltage regulation, the maximum current (in supply circuits are chosen by which one of the
milliamperes) permitted to flow through the following criteria? (Vm is the peak input supply

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voltage to the rectifier circuit used in the (C) Ω (D) 14 Ω

power supply)
(A) The diodes that are to be mand in m Q22 For be Zener diode shown in the figure, the
used in a full wave rectifier bridge Zener voltage at knee is 7 V, the knee current
should be rated 2V rectifier is negligible and the Zener dynamic resistance
equal to V is 10 Ω. If the input voltage Vi range from 10 V
(B) The diodes that are to be mand in m to 16 V, the output voltage V0 ranges from
used in a full wave rectifier bridge
should be rated V rectifier
equal to 2V
(C) All diodes should be rated for Vmonly
(D) All diodes should be rated for 2Vm

Q20 The circuit shown below is the Thevenin’s

equivalent circuit of a centre-tapped full wave (A) 7.00 to 7.99 V (B) 7.14 to 7.29 V
rectifier with diode forward resistance Rf = 100 (C) 7.14 to 7.43 V (D) 7.29 to 7.43 V
Ω, transformer secondary coil resistance RS =
Q23 An symmetrical periodic pulse train of Vin of 10
30 Ω, peak input voltage Vm = 10 V.
V amplitude with on-time TON = 1 ms and off-
What are the values of V and R0, respectively?
time = 1 μs is applied to the circuit shown in
the figure. The diode D1 is ideal.

(A) 10 V, 1000 Ω The difference between the maximum voltage

(B) 6.36 V, 130 Ω and minimum voltage of the output waveform
(C) 6.36 V, 115 Ω v0
(D) 6.54 V, 130 Ω
(in integer) is _______ V.
Q21 In the voltage regulator shown in the figure.
Q24 If cut-in voltage of the diode is 0.8 V then
The load current can vary from mA to 500 mA
minimum value of resistance R2 required for
Assuming that the Zener diode is ideal (i.e. the
Zener knee current is negligibly small and diode to be on is _____

Zener resistance is zero in the breakdown

region). The value of R is]

Q25 Reverse saturation current for diodes is given

as :
(A) 7 Ω (B) 70 Ω

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Q28 Find steady state value of V0, provided Vi = 5

sin(ωt)

Use η = 1
The value of voltage VO is ________

Q29 For the circuit shown is figure,

Q26 Find the value of steady state V0 in the given Given, VT = 26 mV, C1 and C2 are large

circuit. capacitance. Find small signal voltage gain

Vo/Vin

Q30 In the given figure, D1 and D2 are ideal diode.

C1 and C2 are large coupling capacitors. For

very small input signals find the value of

Q27 An ideal diode is placed in circuit shown below.

Assume the resistance R to be very high. Find
average value of V0(t) in steady state.

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Answer Key
Q1 (0.6) Q16 6

Q2 B Q17 B
Q3 11~12 Q18 D
Q4 B Q19 A

Q5 A Q20 B
Q6 C Q21 D
Q7 A Q22 C

Q8 C, D Q23 10~10
Q9 1~1 Q24 1.6~1.6
Q10 A Q25 57~58

Q11 4~4 Q26 20~20

Q12 3~3 Q27 -6~-6
Q13 D Q28 9~9
Q14 C, D Q29 0.75~0.75

Q15 -0.5~-0.5 Q30 0.5~0.8

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