A. Number System (5)
(a) Convert the number 40.12510 into Binary. [2]
(b) Add together the different
number systems, ( 38 + E0416 ) and give the
answer in BCD. [3]
B. Logic Representation. (3)
(c) Find the Boolean expression for the switching circuit below. [1]
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(d) Let p be statement Tom speaks English, and
q the statement Tom speaks
French. Represent the statements below using Boolean logic,
in terms of p and
q.
Tom speaks neither English nor French [1]
(e) Represent the above question (d) using one Logic gate. [1]C. Boolean
Algebra. (12)
(f) Using Boolean algebra and de Morgans Law or otherwise prove
the property
below. [4]
AB+AB=[(A{AB})(B{AB})]
(g) By constructing the Karnaugh Map for the function
F(A,B,C,D) =
( 0,1,5,13) + dont care (4,14)
find the sum of products and product of sums.
[4]
(h) Solve the following using Quine McClusky
the expression,
(
m0,m2, m3 m8, m9,m14,m15)
up to the prime implicants. Indicate the prime implicants clearly.
[4]
D. Sequential Circuits (8)
(i) Give the Characteristic table of a JK flip-flop and convert an
SR to a JK flip-flop.
[4]
(j) A binary cell has the following connections: [4]
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The cell acts as a single bit memory.
Its behaviour is as follows: if select
control S is low, the bit remains unchanged and the output is zero:
if S is high
and the read / write control R/W is high, the bit remains unchanged
and the
output O is the same as the bit; if S is high and R/W is low,
the bit is replaced
with the input I and the output is zero.
Design an implementation of such a cell. Hint: one implementation
can be
constructed by appropriately connecting the following components.
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E. Theory (2)
(k) Explain what is meant by the term semiconductor. [2]
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