The address bus in 8086 microprocessor is __________ bit wide.

Explanation:

8086 Microprocessor Address Bus

Definition: The address bus in a microprocessor is a collection of wires or conductors that are used to transmit the memory addresses from the processor to memory or other devices. The width of the address bus determines the maximum addressing capacity of the microprocessor, i.e., the amount of memory that can be directly accessed.

Address Bus in 8086 Microprocessor: The Intel 8086 microprocessor, introduced in 1978, is a 16-bit microprocessor with a 20-bit address bus. This means that the address bus can carry 20 bits of information at a time.

Working Principle: The 20-bit address bus in the 8086 microprocessor allows it to address up to 2^20 (1,048,576) memory locations. Each memory location corresponds to a byte, so the 8086 can address up to 1MB (megabyte) of memory. The address bus transmits the address from the CPU to the memory or I/O devices, enabling the processor to read from or write to specific memory locations or ports.

Calculation:

To understand the addressing capacity, consider the number of address lines (N) in the address bus. The maximum number of memory locations that can be addressed is given by 2^N. For the 8086 microprocessor with a 20-bit address bus:

Number of addressable memory locations = 2²⁰ = 1,048,576 locations

Since each location stores one byte, the total memory that can be addressed is 1MB (1,048,576 bytes).

Applications: The 8086 microprocessor was widely used in early personal computers, embedded systems, and various industrial control applications. Its addressing capacity and performance made it suitable for a range of tasks during its era.

Correct Option Analysis:

The correct option is:

Option 4: 20 bits

This option correctly states that the address bus in the 8086 microprocessor is 20 bits wide. This width allows the processor to address up to 1MB of memory, as explained in the detailed analysis above