# Digital Circuits Questions and Answers – Random Access Memory – 2

This set of tough Digital Electronic/Circuits Questions focuses on “Random Access Memory-2”.

1. The memory capacity of a static RAM varies from ____________
a) 32 bit to 64 bit
b) 64 bit to 1024 bit
c) 64 bit to 1 Mega bit
d) 512 bit to 1 Mega bit

Explanation: Static RAM(SRAM ) is faster than dynamic RAM(DRAM) as the access time for DRAM is more compared to that of SRAM. The memory capacity of a static RAM varies from 64 bits to 1 Mega bit.

2. The input data bit is written into the cell by setting ____________
a) The flip-flop for 1
b) Resetting the flip-flop
c) The flip-flop for HIGH
d) Both the flip-flop for 1 and resetting the flip-flop

Explanation: The input data bit (1 or 0) is written into the cell by setting the flip-flop for 1 and the resetting the flip-flop for a 0 when the R/W’ line is low, R/W is active-low pin.

3. When the READ/(WRITE)’ line is HIGH then the flip-flop is ____________
a) Activated
b) Deactivated
c) Unaffected
d) Both activated and deactivated

Explanation: When the READ/(WRITE)’ line is HIGH then the flip-flop is unaffected since it’s an active low pin. It means that the stored bit (data) is gated to the data out line.

4. The flip-flop in static memory cell can be constructed using ____________
a) Capacitor or MOSFET
b) FET or JFET
c) Capacitor or BJT
d) BJT or MOSFET

Explanation: The flip-flop in the static memory cell can be constructed using Bipolar Junction Transistor (BJT) and MOSFETs because of it’s storing capability. Also, it’s access time is less and it is faster in operation.

5. Which of the following IC is TTL based static RAM?
a) IC 7488
b) IC 7489
c) IC 7487
d) IC 2114

Explanation: The flip-flop in the static memory cell can be constructed using Bipolar Junction Transistor (BJT) and MOSFETs because of it’s storing capability. Also, it’s access time is less and it is faster in operation. In IC 7489, TTL is used which is static RAM.

6. IC 7489 is of ____________
a) 32 bit
b) 64 bit
c) 512 bit
d) 1024 bit

Explanation: The arrangement of IC 7489 is 16 * 4 = 64 bits. Thus, it has 16 columns and 4 rows.

7. Data is written in IC 7489 through ____________
a) Chip select
b) Enable
c) Data input
d) Memory enable

Explanation: Data can be written into the memory via the data inputs by supplying an address to the SELECT inputs and holding both the memory enable and write enable LOW.

8. The first practical form of Random Access Memory (RAM) was the ____________
a) Cathode tube
b) Data tube
c) Memory tube
d) Select tube

Explanation: Data can be written into the memory via the data inputs by supplying an address to the SELECT inputs and holding both the memory enable and write enable LOW since it’s an active-low pin.

9. Magnetic-core memory was invented in ____________
a) 1946
b) 1948
c) 1947
d) 1945

Explanation: Magnetic-core memory was invented in 1947 and developed up until the mid-1970s. It became a widespread form of random-access memory, relying on an array of magnetized rings. 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).

10. Which of the following RAM is volatile in nature?
a) SRAM
b) DRAM
c) EEPROM
d) Both SRAM and DRAM

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). Both static and dynamic RAM are considered volatile, as their state is lost or reset when power is removed from the system.

11. Which one of the following IC is of 4KB?
a) IC 7488
b) IC 7489
c) IC 7487
d) IC 2114

Explanation: IC 2114 is of 4KB and it is a static RAM. Both static and dynamic RAM are considered volatile, as their state is lost or reset when power is removed from the system.

12. Which of the following IC implements the static MOS RAM?
a) TMS 4015
b) TMS 4014
c) TMS 4016
d) TMS 2114

Explanation: The IC TMS 4016 is a 2KB static MOS RAM. There are eleven address inputs available to select the 2014 locations.

13. What types of arrangements a TMS 4016 has?
a) 1024 * 4
b) 1024 * 8
c) 2048 * 4
d) 2048 * 8

Explanation: The IC TMS 4016 is a 2KB static MOS RAM. There are eleven address inputs available to select the 2014 locations.
Therefore, arrangements in TMS 4016 = 2048 * 8 = 2KB.

14. How many address inputs are available in TMS 4016?
a) 10
b) 9
c) 12
d) 11

Explanation: The IC TMS 4016 is a 2KB static MOS RAM. There are eleven address inputs available to select the 2014 locations.

15. In TMS 4016, the data in/data out are ______________
a) Unidirectional
b) Parallel
c) Serial
d) Bidirectional

Explanation: In TMS 4016, the data in/data out are bidirectional terminal. It means that the input/output can be transmitted or received through the same terminal.

Sanfoundry Global Education & Learning Series – Digital Circuits.

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