# 10CS32 Electronic Circuits VTU 3th Semester Question Bank

Visvesvaraya Technological University - VTU
Question Bank
B.E./B.Tech. DEGREE EXAMINATION
(Regulation/Scheme 2010)
10CS32 Electronic Circuits
Third Semester - 3th
Computer Science Engineering - CSE
(Common to Information Science Engineering)

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10CS32: Electronics Circuits.
Question Bank.
*Refer the circuit diagrams from the PDF file named Circuits.pdf
UNIT –I

1. Discuss with neat sketches, the relation of operating point of the for the transistor for the
following cases: i)Neat saturation region ii)Neat cut=off region ;iii)at the centre of active
region.-----------------------------------------------------------------------------------------------------------------8M
2. For the circuit shown(fig.1) calculate Ib,Ic,Vce,Vc,Ve,Vb,and Vbc. Assume B=100 -----------------8M
3. Explain the basic methods of triggering SCR.-----------------------------------------------------------------4M
4. With a neat figures explain the construction and operational principle of an UJT.--------------10M
5. Explain Thermal runaway with reference to the transistors.---------------------------------------------4M
6. Find the values of the resistors Rb,Rc,Re and the transistor gain B for the circuit shown the fig 4.
given that Ib=40 micro amps, Ic=4mA Ve=2V,Vce=12V and supply voltage VCC=15V.-------------5M
7. Explain the effects of collector resistor, base current and supply voltage on the operating point
of a fixed bias circuit. Which is the ideal position for an operating point on the BJT fixed bias
transistor circuit? Explain the above with neat diagrams.------------------------------------------10M
8. What is the operating point for the following voltage divider bias circuit(fig.8)?-------------------8M

UNIT –II
1. What is the difference between JFET and MOSFET? ----------------------------------------------------- 5M
2. With the help of at fig, explain the construction of N-Channel depletion MOSFET--------------10M
3. Fig.5 shows a biasing configuration using DE-MOSFET. Given that the saturation drain current is
8mA. And the pinch off voltage is -2V.Determine the value of gate-source voltage, drain current
and the drain voltage.---------------------------------------------------------------------------------------------5M
4. Explain with neat sketches, the operation of JFET along with its characteristics curve----------8M
5. Discuss merits, demerits and applications of IGBT’s-------------------------------------------------------7M
6. Explain the working of N-channel E-MOSFET with neat diagram. Explain the output
Characteristics of the same.-------------------------------------------------------------------------------------10M
7. Find the values of voltages Vd and Vc for the circuit shown(Fig.9).Assume β=100.Vbe=0.7v,
Saturation drain current of JFET is-10ma and pinch off voltage is -5V.----------------------------10M

UNIT –III
1. Discuss the classification of the optoelectronic devices in detail----------------------------------------6M
2. Explain with neat sketches the principle of operation of JFET along with its characteristics,
3. Briefly discuss with the necessary diagrams the basic operation and construction of LED. ------6M
4. Define the following terms i)responsivity (R) ii) Noise Equivalent power(NEP)iii)Directivity,
iv)Quantum efficiency V)response time.-------------------------------------------------------------5M
5. What is phototransistor? Draw the schematic symbol of phototransistor. Explain VI
characteristics of phototransistor. ----------------------------------------------------------------------------5M
6. Explain different modes of operation of LCD display------------------------------------------------10M
7. Explain photodiode, phorosensor, photoconductor and photo transistors with necessary
diagrams.----------------------------------------------------------------------------------------------------------10M
8. Find the value of RL for the circuit shown in (fig.10). such that the circuit gives a logic high when
the light incident on it is above 200 lux and the photoconductor has the resistance of 14KΩ at a
light level of 100 lux, α=0.5,power supply voltage is Vcc=10V And reference voltage of zener
diode is 3.5V----------------------------------------------------------------------------------------------------10M
9. A photo diode has a noise current of 1*10-15 A,responsivity of 0.5 A/W,active area of 1mm2 and
rise time of 3.5ns.Determine its i)NEP;ii)Detectivity;iii)D*;iv)Quantum efficiency at 850nm.---4M

UNIT –IV
1. Draw the generalized H-Parameter model of the transistor based amplifier and derive the
expression for: i)current gain ii)input impedance iii)Voltage gain iv)output admittance.------10M
2. With a neat fig, explain the operation of Darlington amplifier.---------------------------------------5M