What is the physical meaning of characteristic impedance?

The characteristic impedance is the ratio of wave voltage to wave current at each point along the line. Physically, the characteristic impedance depends on the cross-sectional geometry of the line, which controls the shunt capacitance per unit length, and the series inductance per unit length of the line.

Why is characteristic impedance important?

It is very important, crucial in fact. For efficient (maximum) power transfer to occur, the characteristic impedance of the transmission line must match the impedance of the load. If output impedance is higher than input impedance, current flow (hence power transfer) is limited in accordance with Ohm’s Law.

How do you determine characteristic impedance?

The characteristic impedance is determined by Z0 = √ ZlZh. where Z0 = V 0/I0. Thus, to determine Z0 we merely plot the input impedance Zi as a function of frequency in the complex plane when the cable is terminated in an arbitrary impedance ZL.

What is the characteristic impedance value of practical cables in practice?

This value lies between 400 and 600 Ω for overhead lines and 40–60 Ω for cables as stated already. VR is the receiving end voltage in kV.

What is the difference between impedance and characteristic impedance?

Characteristic Impedance (Z0) is the impedance with no reflections existing on the transmission line. Here the load impedance and source impedance are matched to the impedance of the transmission line. While input impedance is the ratio of voltage to the current which consists of both the incident and reflected waves.

What is the physical significance of intrinsic impedance?

Intrinsic impedance describes the magnitude of the magnetic and electric fields present in the free space. The derivation of the intrinsic impedance of any uniform medium is dependent on the permittivity and permeability of the medium. When the conductivity of the medium varies, the intrinsic impedance also changes.

Can you measure characteristic impedance?

You cannot use a typical ohmmeter to measure characteristic impedance. Instead of trying to use an ohmmeter we will use the circuit of figure 1. The circuit allows us to generate a pulse of current by toggling the switch. Sometimes the characteristic impedance is called the surge impedance of the coax.

What is the condition for Distortionless transmission line?

Explanation: For a distortionless line, the condition R/L = G/C must be true. On substituting for R = 20, L = 40 mH, C = 40 μF, G = 0.02, we get R/L = 500 and G/C = 500. Thus the line is distortionless.

What is relationship between load and characteristic impedance?

Whenever the transmission line of finite length is terminated by a load impedance that is equal to the characteristic impedance, there is no reflection of signals (according to equation 7). In this case, the input impedance equals characteristic impedance.

What is difference between intrinsic impedance and characteristic impedance?

Characteristic impedance does not even need a transmission line, there is a characteristic impedance associated with wave propagation in any uniform medium. The intrinsic impedance is a measure of the ratio of the electric field to the magnetic field.

What is the value of characteristic impedance for loss free transmission line?

between 400 Ω and 600 Ω
Explanation: Surge impedance is the characteristic impedance of a loss free transmission line. It is the square root of ratio of line impedance(Z) and shunt admittance (Y). Its value varies between 400 Ω and 600 Ω.

What is the characteristic impedance of a circuit?

The characteristic impedance is the ratio of wave voltage to wave current at each point along the line. Physically, the characteristic impedance depends on the cross-sectional geometry of the line, which controls the shunt capacitance per unit length, and the series inductance per unit length of the line.

Is the characteristic impedance independent of the length of the transmission line?

Although an infinite line is assumed, since all quantities are per unit length, the characteristic impedance is independent of the length of the transmission line. The voltage and current phasors on the line are related by the characteristic impedance as:

What is characteristic impedance (Zo)?

Characteristic impedance has exactly the same definition as in the 75-ohm coaxial cable you are used to, except that the transmission is balanced with respect to ground rather than single-ended. Characteristic impedance (Zo) is the most important parameter for any transmission line.

What is the characteristic impedance of sound waves?

Leo L. Beranek, Tim J. Mellow, in Acoustics: Sound Fields and Transducers, 2012 The characteristic impedance is the ratio of the effective sound pressure at a given point to the effective particle velocity at that point in a free, plane, progressive sound wave.