Digital Circuits Questions and Answers – Random Access Memory – 1

This set of Digital Electronics/Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Random Access Memory – 1”.

1. What is the access time?
a) The time taken to move a stored word from one bit to other bits after applying the address bits
b) The time taken to write a word after applying the address bits
c) The time taken to read a stored word after applying the address bits
d) The time taken to erase a stored word after applying the address bits

Answer: c
Explanation: The access time is the time taken to read a stored word after applying the address bits in a MOS EPROM. It is the time required to fetch data from the memory.

2. What are the typical values of tOE?
a) 10 to 20 ns for bipolar
b) 25 to 100 ns for NMOS
c) 12 to 50 ns for CMOS
d) All of the Mentioned

Answer: d
Explanation: The access time is the time taken to read a stored word after applying the address bits in a MOS EPROM. It is the time required to fetch data from the memory. The typical values of tOE (i.e. access time) are 10 to 20 ns for bipolar, 25 to 100 ns for NMOS and 12 to 50 ns for CMOS.

3. Which of the following is not a type of memory?
a) RAM
b) FPROM
c) EEPROM
d) ROM

Answer: c
Explanation: EEPROM (Electrical Erasable Programmable ROM) is not a type of memory because it is used for erasing purpose only. Through EEPROM, data can be erased electrically, thereby consuming less time.

4. The chip by which both the operation of read and write is performed __________
a) RAM
b) ROM
c) PROM
d) EPROM

Answer: a
Explanation: A Random Access Memory (RAM) is a volatile chip memory in which both the read and write operations can be performed. Since it is volatile, therefore it stores data as long as power is on.

5. RAM is also known as __________
a) RWM
b) MBR
c) MAR
d) ROM

Answer: a
Explanation: A Random Access Memory (RAM) is a volatile chip memory in which both the read and write operations can be performed. Since it is volatile, therefore it stores data as long as power is on. RAM is also known as RWM (i.e. Read Write Memory).

6. If a RAM chip has n address input lines then it can access memory locations upto __________
a) 2(n-1)
b) 2(n+1)
c) 2n
d) 22n

Answer: c
Explanation: RAM is a volatile memory, therefore it stores data as long as power is on. RAM is also known as RWM (i.e. Read Write Memory). If a RAM chip has n address input lines then it can access memory locations upto 2n.

7. The n-bit address is placed in the __________
a) MBR
b) MAR
c) RAM
d) ROM

Answer: b
Explanation: The n-bit address is placed in the Memory Address Register (MAR) to select one of 2n memory locations. It stores the address of the instruction which is to be executed next.

8. Which of the following control signals are selected for read and write operations in a RAM?
a) Data buffer
b) Chip select
c) Read and write
d) Memory

Answer: c
Explanation: Read and write are control signals that are used to enable memory for read and write operations respectively.

9. Computers invariably use RAM for __________
a) High complexity
b) High resolution
c) High speed main memory
d) High flexibility

Answer: c
Explanation: RAM is a volatile memory, therefore it stores data as long as power is on. RAM is also known as RWM (i.e. Read Write Memory). Computers invariably use RAM for their high high-speed main memory and then use backup or slower-speed memories to hold auxiliary data.

10. How many types of RAMs are?
a) 2
b) 3
c) 4
d) 5

Answer: a
Explanation: There are two types of RAM and these are static and dynamic. Static RAM(SRAM) is faster than dynamic RAM(DRAM) as the access time for DRAM is more compared to that of SRAM.

11. Static RAM employs __________
a) BJT or MOSFET
b) FET or JFET
c) Capacitor or BJT
d) BJT or MOS

Answer: d
Explanation: Static RAM employs bipolar or MOS flip-flops because both the semiconductor has storing capacity. Thus, it’s access time is less and it is faster in operation.

12. Dynamic RAM employs __________
a) Capacitor or MOSFET
b) FET or JFET
c) Capacitor or BJT
d) BJT or MOS

Answer: a
Explanation: Dynamic RAM employs a capacitor or MOSFET. Thus, it’s access time is more and it is slower in operation.

13. Which one of the following is volatile in nature?
a) ROM
b) EROM
c) PROM
d) RAM

Answer: d
Explanation: RAM is a volatile memory, therefore it stores data as long as power is on. RAM is also known as RWM (i.e. Read Write Memory). RAMs are volatile because the stored data will be lost once the d.c. power applied to the flip-flops is removed.

14. The magnetic core memories have been replaced by semiconductor RAMs, why?
a) Semiconductor RAMs are highly flexible
b) Semiconductor RAMs have highest storing capacity
c) Semiconductor RAMs are smaller in size
d) All of the Mentioned

Answer: d
Explanation: RAM is a volatile memory, therefore it stores data as long as power is on. RAM is also known as RWM (i.e. Read Write Memory). The magnetic core memories have been replaced by semiconductor RAMs because of smaller in size, high storing capacity as well as flexibility.

15. The data written in flip-flop remains stored as long as __________
a) D.C. power is supplied
b) D.C. power is removed
c) A.C. power is supplied
d) A.C. power is removed

Answer: a
Explanation: Since flip-flops are made up of semiconductor materials. So, it can’t accept A.C. source and the data written in flip-flop remains stored as long as the dc power is maintained.

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