Resonant CircuitsThe resonance phenomenon and its characterization
Filter NetworksNetworks with frequency selective characteristics:low-pass, high-pass, band-pass
VARIABLE-FREQUENCY NETWORKPERFORMANCE
RESONANT CIRCUITS
These are circuits with very special frequency characteristics…And resonance is a very important physical phenomenon
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when zero iscircuit each of reactance The
The frequency at which the circuit becomes purely resistive is calledthe resonance frequency
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Properties of resonant circuits
At resonance the impedance/admittance is minimal
Current through the serial circuit/voltage across the parallel circuit canbecome very large (if resistance is small)
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Given the similarities between series and parallel resonant circuits, we will focus on serial circuits
EXAMPLE Determine the resonant frequency, the voltage across eachelement at resonance and the value of the quality factor
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Capacitor and inductor exchange storedenergy. When one is at maximum the other is at zero
EXAMPLE The Tacoma Narrows Bridge Opened: July 1, 1940Collapsed: Nov 7, 1940
Likely cause: windvarying at frequencysimilar to bridgenatural frequency
2.020
FILTER NETWORKS
Networks designed to have frequency selective behavior
COMMON FILTERS
Low-pass filterHigh-pass filter
Band-pass filter
Band-reject filter
Simple low-pass filter
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Simple high-pass filter
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Simple band-pass filter
Band-pass
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Simple band-reject filter
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