5th Class Computers Science Categories of Computers Digital computer

    Digital computer  

A Digital Computer is a computer that stores data in terms of digits (numbers) and proceeds in discrete steps from one state to the next. The word 'digital' stands for discrete (step-by-step) and hence, digital computers can take only discrete values. A digital computer is a combination of electric devices designed to manipulate physical quantities or information that are represented in a digital format. In other words, a digital computer represents data in terms of discrete, numbers and processes data using the standard arithmetic operations. The accuracy obtained in a digital computer is very high. Unlike analog computers which deal with the measurements of physical quantities, digital computers directly count digits (or numbers) that represent letters, numeral s or other special characters. Digital computers are high speed, programmable electronic devices that perform mathematical calculations, compare values and state the results. They recognize data by counting discrete signals representing either a high voltage electrical state (ON) or low voltage electrical state (OFF). Digital computers are used in almost every field of life. Digital computers were originally designed to perform certain numerical calculations. Digital computers come in a wide variety, ranging from tiny, special-purpose devices embedded in cars and other devices to the desktop computer, the minicomputer, the mainframe, and the supercomputer. The impact of the digital computer on-society has been tremendous. It is used to run everything from spacecraft to factories, healthcare systems to telecommunications and banks to household budgets. Since its invention during World War II, the electronic digital computer has become essential to the economies of the developed world. (See Figure 5.1.1)  

   Advantages of Digital Computers

• Digital computer uses binary data strings (0 and 1) to reproduce data.
• Noise and distortions have hardly any impact on its output.
• It makes high-quality data transmission possible.
• It is very precise in its output.      

 Digital Computer has many advantages. Few advantages are given below. Select the correct one.

1. It is very imprecise in its output.

2. It makes high-quality data transmission possible.

3. Noise and distortions have much more impact on its output.

(A) Only 2                                                           

(B) 1 and 2

(C) 1 and 3                                                          

(D) 2 and 3

(E) None of these  

Answer: (a)

Expiation

Correct Option:

(A) Only statement 2 is correct.

Incorrect Options:

(B) Statement 1 is incorrect whereas statement 2 is correct. Therefore, option (B) is incorrect.

(C) Both statements 1 and 3 are incorrect. Therefore, option (C) is incorrect.

(D) Statement 3 is incorrect whereas statement 2 is correct. Therefore, option (D) is incorrect.

(E) All the given statements are not incorrect. Therefore, option (E) is incorrect.  

  Fill in the blanks:

1. A digital computer is a computer that stores data in terms of __________.

2. A digital computer is a combination of electric devices designed to manipulate _______ or information that are represented in a digital format.

3.  Digital computer is invented during_________.

(A) Numbers, Mechanical quantities. World war I

(B) Digits, Physical quantities, World war II

(C) Character, Mechanical quantities, World war III

(D) Digits, Physical quantities. World war I

(E) Character, Mechanical quantities. World war I

Answer: (b)

Explanation

Correct Option:

(B) Options given in (B) are correct.

Incorrect Options:

(A) Options given in (A) are incorrect.

(C) Options given in (C) are incorrect.

(D) Options given in (D) are incorrect.

(E) Options given in (E) are incorrect.