2021-11-11 19:00:01 +00:00
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= Impedance =
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Ac voltage and current are often in phase, in something such as a resistor.
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However, they can become out of phase when passing through a [[Capacitor]] or
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[[Inductor]]. Capacitors are resistant to changes in voltage, causing voltage
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and current to get out of sync. Inductors are resistant to chagnes in current,
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causing voltage to get out of sync.
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2021-11-11 19:15:01 +00:00
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This getting out of sync is called reactance. The total reactance is called
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Impedance. Impedance is measured in Ohms, shown as Z
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2021-11-12 17:45:01 +00:00
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== Inductors ==
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An inductor creates a magnetic field, which when the direction of the voltage
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switches, the field resists this change, creating a phase shift. This causes
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some resistance, which is why impedance is measured in Ohms. The phase shift,
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and therefore the resistance, is directly based on the frequency of the AC
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signal. The relationship is shown below
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X,,l,, = 2(pi)fL
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Where X,,l,, is the inductive reactance (in Ohms),
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f is AC signal frequency (in hz),
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and L is the inductance (in henery)
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*Inductors always make voltage lead current*
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== Capacitors ==
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A capacitor creates an electrostatic field, which swaps which plate of the
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capacitor each charge forms on, when the direction changes. As a result, this
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creates some resistance, measured in Ohms. The phase shift (in current) is
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based on the frequency of the AC signal. The relationship is shown below
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X,,c,, = 1 / 2(pi)fC
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Where X,,c,, is the capactive reactance (in Ohms),
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f is the AC signal frequency (in hz),
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and C is the capacitance (in f)
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