To understand the design and operation of these logic circuits, one needs to have a good knowledge about Boolean algebra and logic gates. Best examples of such circuits are Encoders and Decoders, Multiplexers and De-multiplexers, Adders, Subtractors etc. The output of a combinational logic circuit depends only on the present state of the inputs and nothing else. A combinational logic circuit is a system of logic gates consisting of only outputs and inputs. It can be a simple binary to decimal decoder or a BCD to 7 segment decoder.Īnother relevant section is the combinational logic circuitry. A decoder is a combinational circuit which is used to convert a binary or BCD (Binary Coded Decimal) number to the corresponding decimal number. The first and foremost aspect of this circuit is decoder. Related Post: Water Level Indicator Theory Behind the Circuit: Using Karnough’s map, logic circuitry for each input to the display is designed. The logic circuit is designed with 4 inputs and 7 outputs, each representing an input to the display IC. The basic idea involves driving a common cathode 7-segment LED display using combinational logic circuit. Principle Behind Display Decoder Circuit: Even though commercial BCD to 7 segment decoders are available, designing a display decoder using logic gates may prove to be beneficial from economical as well as knowledge point of view. Here we design a simple display decoder circuit using logic gates. It generally has 4 input lines and 7 output lines. A display decoder is used to convert a BCD or a binary code into a 7 segment code used to operate a 7 segment LED display.

Multisim 7 segment display imput