Balun stands for Balance to unbalance. It can also be used to connect the unbalanced transmission line to a balance load such as antenna. It consist of special type of transformer with an unbalanced primary and centre tapped secondary winding. Baluns is used for matching two wires line to co-axial cable. It is used in Tv receiver for impedance matching. Its input is 300-75ohm. It consist of two quarter wave length.