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  2. Electrical impedance - Wikipedia

    en.wikipedia.org/wiki/Electrical_impedance

    In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]

  3. Characteristic impedance - Wikipedia

    en.wikipedia.org/wiki/Characteristic_impedance

    The characteristic impedance of an infinite transmission line at a given angular frequency is the ratio of the voltage and current of a pure sinusoidal wave of the same frequency travelling along the line. This relation is also the case for finite transmission lines until the wave reaches the end of the line. Generally, a wave is reflected back ...

  4. Smith chart - Wikipedia

    en.wikipedia.org/wiki/Smith_chart

    Using the Smith chart, the normalised impedance may be obtained with appreciable accuracy by plotting the point representing the reflection coefficient treating the Smith chart as a polar diagram and then reading its value directly using the characteristic Smith chart scaling. This technique is a graphical alternative to substituting the values ...

  5. Impedance matching - Wikipedia

    en.wikipedia.org/wiki/Impedance_matching

    Impedance is the opposition by a system to the flow of energy from a source. For constant signals, this impedance can also be constant. For varying signals, it usually changes with frequency. The energy involved can be electrical, mechanical, acoustic, magnetic, electromagnetic, or thermal. The concept of electrical impedance is perhaps the ...

  6. RC time constant - Wikipedia

    en.wikipedia.org/wiki/RC_time_constant

    The RC time constant, denoted τ (lowercase tau), the time constant (in seconds) of a resistor–capacitor circuit (RC circuit), is equal to the product of the circuit resistance (in ohms) and the circuit capacitance (in farads): It is the time required to charge the capacitor, through the resistor, from an initial charge voltage of zero to ...

  7. Wave impedance - Wikipedia

    en.wikipedia.org/wiki/Wave_impedance

    The wave impedance of an electromagnetic wave is the ratio of the transverse components of the electric and magnetic fields (the transverse components being those at right angles to the direction of propagation). For a transverse-electric-magnetic (TEM) plane wave traveling through a homogeneous medium, the wave impedance is everywhere equal to ...

  8. Reflection coefficient - Wikipedia

    en.wikipedia.org/wiki/Reflection_coefficient

    Reflection coefficient. In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected wave to the incident wave, with each expressed as phasors.

  9. RL circuit - Wikipedia

    en.wikipedia.org/wiki/RL_circuit

    t. e. A resistor–inductor circuit (RL circuit), or RL filter or RL network, is an electric circuit composed of resistors and inductors driven by a voltage or current source. [1] A first-order RL circuit is composed of one resistor and one inductor, either in series driven by a voltage source or in parallel driven by a current source.