Editing Smith chart (section)

====Regions of the {{math|Z}} Smith chart====
If a polar diagram is mapped on to a [[cartesian coordinate system]] it is conventional to measure angles relative to the positive {{mvar|x}}-axis using a [[counterclockwise]] direction for positive angles. The magnitude of a complex number is the length of a straight line drawn from the [[origin (mathematics)|origin]] to the point representing it. The Smith chart uses the same convention, noting that, in the normalised impedance plane, the positive {{mvar|x}}-axis extends from the center of the Smith chart at <math>\, z_\mathsf{T} = 1 \pm j 0 \,</math> to the point <math>\, z_\mathsf{T} = \infty \pm j \infty \,.</math> The region above the x-axis represents inductive impedances (positive imaginary parts) and the region below the {{mvar|x}}-axis represents capacitive impedances (negative imaginary parts).

If the termination is perfectly matched, the reflection coefficient will be zero, represented effectively by a circle of zero radius or in fact a point at the centre of the Smith chart. If the termination was a perfect open circuit or [[short circuit]] the magnitude of the reflection coefficient would be unity, all power would be reflected and the point would lie at some point on the unity circumference circle.