What is resonant circuit?


by beanryu
Tags: circuit, resonant
beanryu
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#1
Nov26-05, 06:37 PM
P: 96
What is resonant circuit? and specifically what is RLC circuit?
THANX ALOT!
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ranger
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#2
Nov26-05, 08:16 PM
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An RLC circuit is a kind of electrical circuit composed of a resistor (R), an inductor (L), and a capacitor (C). For more info read http://en.wikipedia.org/wiki/RLC_circuits

In an electrical circuit, resonance occurs at a particular frequency when the inductive reactance and the capacitive reactance are of equal magnitude, causing electrical energy to oscillate between the magnetic field of the inductor and the electric field of the capacitor.

Resonance occurs because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor and the discharging capacitor provides an electric current that builds the magnetic field in the inductor, and the process is repeated. An analogy is a mechanical pendulum.

At resonance, the series impedance of the two elements is at a minimum and the parallel impedance is a maximum. Resonance is used for tuning and filtering, because resonance occurs at a particular frequency for given values of inductance and capacitance. Resonance can be detrimental to the operation of communications circuits by causing unwanted sustained and transient oscillations that may cause noise, signal distortion, and damage to circuit elements.
http://en.wikipedia.org/wiki/Resonant

Additional info >>> http://hyperphysics.phy-astr.gsu.edu...ic/serres.html
Matrax
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#3
Nov27-05, 02:30 AM
P: 6
A circuit that has a set capasitance and Inductance, will "Resonate" at a set frequency of AC Current. Resonace occurs when Capasitive Reactance ( XC= 1/2pieFC) and Inductive reactance (XL = 2pieFL) (L = Inductance in Henrys, C = Capasitance in Farads) are equal to each other. To understand how this really works, you need to know the effects of inductance and capasitance on an AC Circuit. Inductance changes the phase angle of an AC sine wave by increasing the angle, Capasitance reduces the angle. When AC meets a capasitance or inductance, it reacts with them, and produces a resistance that only an AC current at the given frequency would see. When the frequency reachs the resonate level (given by Fr = 1/2pie(LC)^1/2), the reactances cancel each other out and the AC current basicly ignores them and resistance is figured by the Ohmic resistance of the coil that provides the inductance.

Circuits that use resonance in everyday use:
AM/FM recievers
Class-C Amlifiers
Metal detectors

beanryu
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#4
Nov29-05, 10:08 PM
P: 96

What is resonant circuit?


so capacitance reduce the phase angle and inductance increase the phase angle? and by the way,

here is what I think inductors do
they allow current to follow across it and store energy by creating magatic field.

Is this correct, what other basic thing does inductors do?
ranger
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#5
Nov29-05, 10:19 PM
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here is what I think inductors do
they allow current to follow across it and store energy by creating magatic field.

Is this correct, what other basic thing does inductors do?
Yes that is correct. It stores energy in a magnetic field that is created by current flowing through its coils.

I'm sure after you read this, you will have a better understanding of inductors and be able to answer your second question.

Please also read this thread. I've attempted to only provide a very brief intro into the workings of the inductor. Please note how I often compare it to the capacitor.


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