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Name:Student No.

Q1. Calculate the value of VR1 from(Assume constant voltage dro

diodes D1 and D2 with cut-in

EEE 267

CT 1

Time: 20 minutes

the following circuit.p models for the given

oltage, Vγ = 0.70 V)

8

Q2. Consicirc

(Assume

D1

(a) Draw

(v0(t 

 

(b) Also s

foll

der vs(t )=10 sin (100 

t ) volt  in the foit.

constant voltage drop model for the give

ith cut-in voltage, Vγ = 0.70 V)

he wave-shapes of the input (vs(t )) and

)) voltages superimposed in a same plot.

ketch the voltage transfer characteristic

wing circuit.

v0 

llowing

n diode

output

6

of the

6

vs 

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EEE 267

CT 2

Time: 20 minutes

Name:

Student No.

Q1. Fig.1 shows a circuit diagram of a clipper circuit. The applied sinusoidal voltagevs(t ) is 10 sin (2000 

t ) voltage.The voltage wave-shapes of the input (vs(t )) and output (v0(t )) voltages are shown in Fig. 2 superimposed on each other.

Now, calculate the value of DC voltage sources V1 and V2 shown in Fig. 1. (Assume constant voltage drop models forthe given diodes D1 and D2 with cut-in voltage, Vγ = 0.70 V) (8)

Q2. Also calculate the value of t D1 and t D2 using the information in Figs. 1 and 2. (12)

Fig. 1: Circuit diagram Fig. 2: Waveforms of vs(t ) and vo(t )

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Student No.

Q1. In the following circuit shown iNow tick on the correct

The npn transistor is ope

a) cut-off mode

b) saturation m

c) Forward-acti

Q2. In the following circuit shown i

value of V0

Fig. 1: Circuit diagram

Student No.

Q1. In the following circuit shown i

Now tick on the correct

The npn transistor is ope

a) cut-off modeb) saturation mc) Forward-acti

Q2. In the following circuit shown i

value of V0

Fig. 1: Circuit diagram

n Fig. 1, it is given that VCC=10V, RB=10answer:

rating on

ode

ve operating mode

n Fig. 1, consider VCC=10V, RB=100K,

n Fig. 1, it is given that VCC=10V, RB=10

answer:

rating on

odeve operating mode

n Fig. 1, consider VCC=10V, RB=100K,

K, RC=5K and V0=10V.

C=1K, VBB=5V and β = 100. Now, calcu

K, RC=5K and V0=10V.

C=1K, VBB=5V and β = 100. Now, calcu

(8)

late the

(17)

(8)

late the

(17)

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EEE 267

CT 4

A separately excited dc generator with a field current of 2.5 amp, when running at 1200 rpmsupplies 200 amp at 125V to a load circuit of constant resistance. Armature resistance is

0.04 and total drop at brushes is 2V. Determine the

i) Generated voltage (5)

ii) Value of constant resistance (5)

Now the speed is increased to 1600 rpm and the field current is reduced to 80%. The relation

between the field current (If ) in amp and produced field flux (φ) in Wb can be expressed as

φ = 1-exp(-If ). Calculate

iii) Changed generated voltage (5)

iv) Changed current in load circuit (10)

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EEE267

CT5

Name:

Student No.

The equivalent low-side parameters of a 250-KVA, 480-4160V, 60-Hz transformer are Req,LS=

0.00920 and Xeq,LS= 0.00920. The transformer is operating in the step-up mode and is

delivering half of the rated current at rated voltage to a 0.9 pf leading. Determine the voltage

regulation.