Test: Combinational Circuit- 1

The Product of Sum (POS) expression comes from the fact that two or more sums (OR's) are added (AND'ed) together. That is the outputs from two or more OR gates are connected to the input of an AND gate so that they are effectively AND'ed together to create the final (OR AND) output.

In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several analog or digital input signals and forwards the selected input to a single output line.

The quantity 837 is first converted to BCD representation then it is incremented by 3 bit by bit.

A half adder is also known as XOR gate because XOR is applied to both inputs to produce sum.

Comparison between serial and parallel adder reveals that serial adder is serial adder is a sequential circuit. A parallel adder is a combinational circuit. In serial adder, propagation delay is less. In parallel adder, propagation delay is present from input carry to output carry.

We can construct a m-bit parallel adder by,
(i) m-full adders OR
(ii) (m - 1) full adders and one half adder OR
iii) (2m - 1 ) full adders and (n - 1) OR GATES

Therefore the above circuit performed exclusive NOR gate.