# Universal Shift Registers MCQ’Q

This set of Digital Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Universal Shift Registers”.

1. A bidirectional 4-bit shift register is storing the nibble 1101. Its input is HIGH. The nibble 1011 is waiting to be entered on the serial data-input line. After three clock pulses, the shift register is storing ________
a) 1101
b) 0111
c) 0001
d) 1110

2. To operate correctly, starting a ring shift counter requires __________
a) Clearing all the flip-flops
b) Presetting one flip-flop and clearing all others
c) Clearing one flip-flop and presetting all others
d) Presetting all the flip-flops

3. A sequence of equally spaced timing pulses may be easily generated by which type of counter circuit?
a) Ring shift
b) Clock
c) Johnson
d) Binary

4. A 4-bit shift register that receives 4 bits of parallel data will shift to the ________ by ________ position for each clock pulse.
a) Right, one
b) Right, two
c) Left, one
d) Left, three

5. How is a strobe signal used when serially loading a shift register?
a) To turn the register on and off
b) To control the number of clocks
c) To determine which output Qs are used
d) To determine the FFs that will be used

6. What are the three output conditions of a three-state buffer?
a) HIGH, LOW, float
b) High-Z, 0, float
c) Negative, positive, 0
d) 1, Low-Z, float

7. How many clock pulses will be required to completely load serially a 5-bit shift register?
a) 2
b) 3
c) 4
d) 5

8. An 8-bit serial in/serial out shift register is used with a clock frequency of 150 kHz. What is the time delay between the serial input and the Q3 output?
a) 1.67 s
b) 26.67 s
c) 26.7 ms
d) 267 ms

9. The primary purpose of a three-state buffer is usually ____________
a) To provide isolation between the input device and the data bus
b) To provide the sink or source current required by any device connected to its output without loading down the output device
c) Temporary data storage
d) To control data flow

10. What is the difference between a ring shift counter and a Johnson shift counter?
a) There is no difference
b) A ring is faster
c) The feedback is reversed
d) The Johnson is faster