EC GATE 2009 (Test 1)



Tag: ec gate 2009
Q.1
In a microprocessor, the service routine for a certain interrupt starts from a fixed location of memory which cannot be externally set, but the interrupt can be delayed or rejected Such an interrupt is
A. non-maskable and non-vectored
B. maskable and non-vectored
C. non-maskable and vectored
D. maskable and vectored
Answer : Option D
Explaination / Solution:

Vectored interrupts : Vectored interrupts are those interrupts in which program control transferred to a fixed memory location. Maskable interrupts : Maskable interrupts are those interrupts which can be rejected or delayed by microprocessor if it is performing some critical task.

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Q.2
In the circuit shown below, the op-amp is ideal, the transistor has VBE = 0.6 V and  β= 150. Decide whether the feedback in the circuit is positive or negative and determine the voltage V at the output of the op-amp.

A. Positive feedback, V = 10 V.
B. Positive feedback, V = 0 V
C. Negative feedback, V = 5 V
D. Negative feedback, V = 2 V
Answer : Option D
Explaination / Solution:

The circuit is shown in fig below

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Q.3
If X = 1 in logic equation Then
A. Y=Z
B.
C. Z=1
D. Z=0
Answer : Option D
Explaination / Solution:


Substituting X = 1 and we get
                                                                   1 + A = 1 and 0 + A = A

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Q.4
What are the minimum number of 2- to -1 multiplexers required to generate a 2- input AND gate and a 2- input Ex-OR gate
A. 1 and 2
B. 1 and 3
C. 1 and 1
D. 2 and 2
Answer : Option A
Explaination / Solution:

The AND gate implementation by 2:1 mux is as follows


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Q.5
What are the counting states (Q1,Q2) for the counter shown in the figure below

A. 11,10,00,11,10,...
B. 01,10,11,00,01...
C. 00,11,01,10,00...
D. 01,10,00,01,10...
Answer : Option A
Explaination / Solution:

The given circuit is as follows.

The truth table is as shown below. Sequence is 00, 11, 10, 00 ...


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Q.6
If segments a to g are considered as functions of P1 and P2, then which of the following is correct

A.
B.
C.
D.
Answer : Option B
Explaination / Solution:



LED d is 1 all condition and also it depends on
d = c + e

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Q.7
What are the minimum numbers of NOT gates and 2 - input OR gates required to design the logic of the driver for this 7 - Segment display
A. 3 NOT and 4 OR
B. 2 NOT and 4 OR
C. 1 NOT and 3 OR
D. 2 NOT and 3 OR
Answer : Option D
Explaination / Solution:

As shown in previous solution 2 NOT gates and 3-OR gates are required.

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Q.8
In the following a stable multivibrator circuit, which properties of  V0(t) depend on R2?

A. Only the frequency
B. Only the amplitude
C. Both the amplitude and the frequency
D. Neither the amplitude nor the frequency
Answer : Option A
Explaination / Solution:

The R2  decide only the frequency.

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Q.9
A fully charged mobile phone with a 12 V battery is good for a 10 minute talktime. Assume that, during the talk-time the battery delivers a constant current of 2 A and its voltage drops linearly from 12 V to 10 V as shown in the figure. How much energy does the battery deliver during this talk-time?

A. 220 J
B. 12 kJ
C. 13.2 kJ
D. 14.4 J
Answer : Option C
Explaination / Solution:

The energy delivered in 10 minutes is


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Q.10
The full form of the abbreviations TTL and CMOS in reference to logic families are
A. Triple Transistor Logic and Chip Metal Oxide Semiconductor
B. Tristate Transistor Logic and Chip Metal Oxide Semiconductor
C. Transistor Transistor Logic and Complementary Metal Oxide Semiconductor
D. Tristate Transistor Logic and Complementary Metal Oxide Silicon
Answer : Option C
Explaination / Solution:

TTL -> Transistor - Transistor logic CMOS -> Complementary Metal Oxide Semi-conductor

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