BCD equivalent of decimal number 43 is

Question

Question

This question was previously asked in

IPRC ISRO Technical Assistant Electronics 21 April 2018 Official Paper

Answer 1

Concept:

8421 is also known as BCD code
BCD is a weighted code.
In weighted codes, each successive digit from right to left represents weights equal to some specified value, and to get the equivalent decimal number to add the products of the weights by the corresponding binary digit.

The following represents the 4-bit binary representation of decimal values:

Application:

From the above Table:

4 = 0100

3 = 0011

43 = 0100 0011 in BCD

26 June 1

A number with 'n' decimal digit will require 4k bits in BCD.
Ex- Decimal 396 is represented in BCD with 12 bits as 0011 1001 0110, with each group of 4 bits representing one decimal digit.
As the decimal digits relating to 1010, 1011, 1100, 1101, 1110, and 1111 do not exist, these are invalid.