How does a BCD counter operate?

A BCD (Binary-Coded Decimal) counter operates by representing each decimal digit using a fixed number of binary bits. Specifically, it utilizes 4 bits to encode each digit from 0 to 9. This means that the counter can represent any decimal number by translating each decimal digit into its corresponding binary form.

For example, the decimal number "57" would be represented in BCD as two separate groups of bits: "0101" for the digit "5" and "0111" for the digit "7". This method allows for straightforward conversion and manipulation of decimal numbers in a digital format. Hence, it is particularly useful in applications where decimal representation is needed or when displaying values on devices like digital clocks or calculators.

The other options describe counting systems that do not conform to the BCD standard. A binary counter counts only in base 2, where each digit represents a power of 2, whereas a hexadecimal counter uses base 16, requiring more bits to represent larger numbers. The octal format, which is base 8, also necessitates a different grouping and representation. Therefore, by using 4 bits for each digit, the BCD counter uniquely serves to bridge the gap between binary representation and decimal systems.