Balance and Symmetry
A balanced circuit will normally show a symmetry of its components about a horizontal line mid-way between the two conductors (example in figure 3). This is different from what is normally meant by a symmetrical circuit which is a circuit showing symmetry of its components about a vertical line at its midpoint. An example of a symmetrical circuit is shown in figure 2. Circuits designed for use with balanced lines will often be designed to be both balanced and symmetrical as shown in figure 4. The advantages of symmetry are that the same impedance is presented at both ports and that the circuit has the same effect on signals travelling in both directions on the line.
Balance and symmetry are usually associated with reflected horizontal and vertical physical symmetry respectively as shown in figures 1 to 4. However, physical symmetry is not a necessary requirement for these conditions. It is only necessary that the electrical impedances are symmetrical. It is possible to design circuits that are not physically symmetrical but which have equivalent impedances which are symmetrical.
Read more about this topic: Balanced Circuit
Famous quotes containing the words balance and/or symmetry:
“At last I feel the equal of my parents. Knowing you are going to have a child is like extending yourself in the world, setting up a tent and saying “Here I am, I am important.” Now that I’m going to have a child it’s like the balance is even. My hand is as rich as theirs, maybe for the first time. I am no longer just a child.”
—Anonymous Father. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 5 (1978)
“What makes a regiment of soldiers a more noble object of view than the same mass of mob? Their arms, their dresses, their banners, and the art and artificial symmetry of their position and movements.”
—George Gordon Noel Byron (1788–1824)