Digital electronics is the field of electronics engineering that involves the study of digital signals and the engineering of devices that use or produce them. Digital electronics is in contrast to analog electronics and analog signals. Digital electronic circuits are usually designed from large assemblies of logic gates, often packaged in integrated circuits. The history of Digital Electronics dates back to 1705 when the binary number system was refined by Gottfried Wilhelm Leibniz. Modern-day digital electronics involves high-speed digital devices wherein faster logic can accomplish multiple operations very quickly. Modern digital electronic logic can do switching as much as up to 5 GHz. Given below are the top 10 Digital Electronics MCQs with brief explanatory answers and solutions.

## The field of Digital Electronics is linked to

The field of Digital Electronics is linked to:

- Study of digital signals
- Study of circuits made from large assemblies of logic gates
- Digital design that uses CMOS logic
- All of these

Correct answer: 4. All of these

## Modern-day most common digital integrated circuits built use

Modern-day most common digital integrated circuits built use

- Mechanical relay logic
- TTL Logic
- CMOS logic
- Vacuum tube logic

Correct answer: 3. CMOS logic

Explanation: CMOS logic uses Complementary metal-oxide–semiconductors also known as complementary-symmetry metal-oxide. It is a semiconductor that is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is utilized for constructing integrated circuit (IC) chips and microprocessors, microcontrollers as well as the memory chips such as CMOS BIOS, and other digital logic circuits.

## Which of the following is a type of digital logic circuit

Which of the following is a type of digital logic circuit:

- Combinational logic circuits
- Sequential logic circuits
- Both of these
- None of these

Correct answer: 3. Both of these

Explanation: A combinational logic circuit is a digital circuit whose output only depends on the current state of its inputs. While a sequential logic circuit is a type of circuit whose output depends on the present value of its input signals and on the sequence of past inputs, the input history. Both combinational and sequential logic circuits are types of digital logic circuits. Hence 3. is the correct answer.

In automata theory, sequential logic is a type of logic circuit whose output depends on the present value of its input signals and on the sequence of past inputs, the input history.

## The memory which uses one transistor and one capacitor as basic memory unit

The memory which uses one transistor and one capacitor as basic memory unit:

- SRAM
- DRAM
- Both of these
- None of these

Correct answer: 2. DRAM

Explanation: SRAM in full known as Static Random Access Memory is made up of CMOS technology. It uses six transistors. Whereas DRAM or Dynamic Random Access Memory uses one MOSFET and one capacitor for storing one bit.

Static RAM ( Random Access Memory ) is constructed by using two or more BJT or MOSFET, one for each stored bit. But in DRAM ( Dynamic Random Access Memory ) uses one MOSFET and one capacitor for storing one bit. Here transistor works as a switch and the capacitor stored binary information as electric charges.

Description | SRAM | DRAM |
---|---|---|

Density | Less dense | Highly dense |

One Single block of memory requires | 6 transistors | Only one transistor. |

Power consumption | Low | High |

Construction | Comparatively complex and uses transistors and latches | Simple and uses capacitors and very few transistors. |

Speed | Faster | Slower |

Size | Small | Large |

Cost | Expensive | Cheap |

Application | Cache memory | Main memory |

## The digital logic gate whose output goes HIGH to a logic level 1 only when one or more of its inputs are HIGH

The digital logic gate whose output goes HIGH to a logic level 1 only when one or more of its inputs are HIGH:

- AND
- OR
- NAND
- NOR

Correct answer: 2. OR Gate

Explanation:

## In binary number system the first digit (bit) from right to left is named as

In binary number system the first digit (bit) from right to left is named as

- First Bit
- Last Bit
- LSB, Least Significant Bit
- MSB, Most Significant Bit

Correct answer: 3. LSB, Least Significant Bit

## Boolean algebra is also known as

Boolean algebra is also known as

- Counting algebra
- Gate algebra
- Switching algebra
- Transistor algebra

Correct answer: 3. Switching algebra

Explanation: Since Boolean Algebra only has two states either 0 or 1 state. Switching algebra is the other name given to Boolean algebra, as it also have only two states either ON or OFF state i.e. 1 or 0

## Truth table is used to express

Truth table is used to express

- Boolean map
- Boolean matrix
- Boolean addition
- Boolean expression

Correct answer: 4. Boolean expression

## Maximum number in decimal that can be represented by 4 bits of binary is

Maximum number in decimal that can be represented by 4 bits of binary is

- 3
- 8
- 15
- 16

Correct answer: 3. 15

Explanation:

Formula: Maximum number =

Where n is the number of bits.

Max Number represented by 4 bits = 24 – 1 ⇒ 15

## If J and K are shorted (J = K) in a JK flip-flop, the circuit made is

If J and K are shorted (J = K) in a JK flip-flop, the circuit made is:

- K flip-flop
- T flip-flop
- SR flip-flop
- Shorted JK flip-flop

Correct answer: 2. T flip-flop

Explanation:

The T flip-flop is actually a JK flip-flop with the J and K inputs shorted. A T flip-flop toggles its output when a 1 is provided at input, otherwise output does not change.

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