# Electronics and Communication Engineering - Exam Questions Papers

1.
A ramp input applied to a unity feedback system results in 5% steady state error. The type number and zero frequency gain of the system are respectively.
1 and 20
0 and 20
0 and 1/20
1 and 1/20
Explanation:

ess = 5% ⇒ .05

.

2.
A fair coil is tossed 10 times. What is the probability that ONLY the first two tosses will yield heads?
Explanation:

Use ncr, (p)r (q)n-r [for any two losses yield head].

But in present case it is required case it is only for first two tosses. Thus in this case 10 times.

3.
The equation sin (z) = 10 has
no real or complex solution
exactly two distinct complex solutions
a unique solution
an infinite number of complex solutions
Explanation:

Since value lies between - 1 and + 1. Therefore no real or complex solution exists.

4.
Given If , then the value of K is
1
2
3
4
Explanation:

.

5.
Consider the Schmitt trigger circuit shown below. A triangular wave which goes from - 12 V to 12 V is applied to the inverting input of the op-amp. Assume that the output of the op-amp moves from +15 V to -15 V. The voltage at the non-inverting switches between
-12 V and +12 V
-7.5 V and +7.5 V
-5 V and +5 V
0 V and 5 V