Combinational logic circuit

Combinational digital logic circuits are basically made up of digital logic gates like AND gate, OR gate, NOT gate and universal gates (NAND gate and NOR gate).All these gates are combined together to form a complicated switching circuit. The logic gates are building blocks of combinational logic circuits. In a combinational logic circuit, the output at any instant of time depends only on present input at that particular instant of time and combinational circuits do not have any memory devices.

Encoders and Decoders are examples of combinational circuit. A decoder converts the binary coded data at its present input into a number of different output lines. Other examples of combinational switching circuits are half adder and full adder, encoder, decoder, multiplexer, de-multiplexer, code converter etc.

Combinational circuits are used in microprocessor and microcontroller for designing the hardware and software components of a computer.

Classification of combinational digital logic circuits

Combinational digital logic circuits are classified into three major parts – arithmetic or logical functions, data transmission and code converter.

The following chart will elaborate the further classifications of combinational digital logic circuit.