The Telegrapher's equations are a set of partial differential
equations that describe the behavior of electrical signals traveling
along a transmission line. They are widely used in the analysis and
modeling of transmission lines, including homogeneous transmission lines
like coaxial cables and parallel-plate transmission lines.
The Telegrapher's equations consist of two equations:
Voltage Equation (also known as the "Kirchhoff's voltage law" equation):
∂V(x,t)/∂x = -L ∂I(x,t)/∂t - R I(x,t)
This equation relates the voltage (V) along the transmission line with
the current (I) flowing through it. The left side of the equation
represents the rate of change of voltage with respect to the position
(x) along the line, while the right side represents the effects of
inductance (L) and resistance (R) on the current.
Current Equation (also known as the "Kirchhoff's current law" equation):
∂I(x,t)/∂x = -C ∂V(x,t)/∂t - G V(x,t)
This equation relates the current (I) along the transmission line with
the voltage (V) across it. The left side represents the rate of change
of current with respect to the position (x), while the right side
represents the effects of capacitance (C) and conductance (G) on the
voltage.
In these equations, x represents the position along the
transmission line, t represents time, and L, R, C, and G are the
per-unit-length inductance, resistance, capacitance, and conductance of
the line, respectively.
By solving the Telegrapher's equations,
various properties of the transmission line can be determined, such as
the propagation velocity, impedance, reflection coefficient, and
attenuation of electrical signals. These equations serve as fundamental
tools for the analysis and design of transmission lines in various
fields, including telecommunications, RF engineering, and signal
integrity analysis.
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