What electrical parameter defines the surge impedance of a transmission line?

The surge impedance of a transmission line is defined by both the inductance and capacitance of the line. This parameter is crucial in understanding how electrical signals propagate through the line. Surge impedance is a characteristic impedance that relates to the line's ability to transmit electrical energy without reflection. It is derived from the ratio of the square root of the inductance per unit length (L) to the capacitance per unit length (C) of the transmission line, typically represented as:

[ Z_0 = \sqrt{\frac{L}{C}} ]

When both inductance and capacitance are taken into account, they help determine the line's surge impedance. This understanding is essential for engineers designing transmission systems since it impacts signal integrity, performance, and the effectiveness of power delivery. High or low surge impedance can significantly affect how transients and steady states behave in a circuit, contributing to various phenomena such as reflections and distortions of signals.