Digital Electronics/Circuits Multiple Choice Questions on “Counters”.
1. In digital logic, a counter is a device which ____________
A. Counts the number of outputs
B. Stores the number of times a particular event or process has occurred
C. Stores the number of times a clock pulse rises and falls
D. Counts the number of inputs
Answer: B
Clarification: In digital logic and computing, a counter is a device which stores (and sometimes displays) the number of times a particular event or process has occurred, often in relationship to a clock signal.
2. A counter circuit is usually constructed of ____________
A. A number of latches connected in cascade form
B. A number of NAND gates connected in cascade form
C. A number of flip-flops connected in cascade
D. A number of NOR gates connected in cascade form
Answer: C
Clarification: A counter circuit is usually constructed of a number of flip-flops connected in cascade. Preferably, JK Flip-flops are used to construct counters and registers.
3. What is the maximum possible range of bit-count specifically in n-bit binary counter consisting of ‘n’ number of flip-flops?
A. 0 to 2n
B. 0 to 2n + 1
C. 0 to 2n – 1
D. 0 to 2n+1/2
Answer: C
Clarification: The maximum possible range of bit-count specifically in n-bit binary counter consisting of ‘n’ number of flip-flops is 0 to 2n-1. For say, there is a 2-bit counter, then it will count till 22-1 = 3. Thus, it will count from 0 to 3.
4. How many types of the counter are there?
A. 2
B. 3
C. 4
D. 5
Answer: B
Clarification: Counters are of 3 types, namely, (i)asynchronous/synchronous, (ii)single and multi-mode & (iii)modulus counter. These further can be subdivided into Ring Counter, Johnson Counter, Cascade Counter, Up/Down Counter and such like.
5. A decimal counter has ______ states.
A. 5
B. 10
C. 15
D. 20
Answer: B
Clarification: Decimal counter is also known as 10 stage counter. So, it has 10 states. It is also known as Decade Counter counting from 0 to 9.
6. Ripple counters are also called ____________
A. SSI counters
B. Asynchronous counters
C. Synchronous counters
D. VLSI counters
Answer: B
Clarification: Ripple counters are also called asynchronous counter. In Asynchronous counters, only the first flip-flop is connected to an external clock while the rest of the flip-flops have their preceding flip-flop output as clock to them.
7. Synchronous counter is a type of ____________
A. SSI counters
B. LSI counters
C. MSI counters
D. VLSI counters
Answer: C
Clarification: Synchronous Counter is a Medium Scale Integrated (MSI). In Synchronous Counters, the clock pulse is supplied to all the flip-flops simultaneously.
8. Three decade counter would have ____________
A. 2 BCD counters
B. 3 BCD counters
C. 4 BCD counters
D. 5 BCD counters
Answer: B
Clarification: Three decade counter has 30 states and a BCD counter has 10 states. So, it would require 3 BCD counters. Thus, a three decade counter will count from 0 to 29.
9. BCD counter is also known as ____________
A. Parallel counter
B. Decade counter
C. Synchronous counter
D. VLSI counter
Answer: B
Clarification: BCD counter is also known as decade counter because both have the same number of stages and both count from 0 to 9.
10. The parallel outputs of a counter circuit represent the _____________
A. Parallel data word
B. Clock frequency
C. Counter modulus
D. Clock count
Answer: D
Clarification: The parallel outputs of a counter circuit represent the clock count. A counter counts the number of times an event takes place in accordance to the clock pulse.