Determining the type of AC filter.

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To determine the type of AC filter, analyze the impedance behavior of capacitors, inductors, and resistors at various frequencies. Capacitors exhibit low impedance at high frequencies and high impedance at low frequencies, while inductors show the opposite behavior. Resistors maintain constant impedance regardless of frequency. For series and parallel resonant circuits, impedance characteristics change significantly at resonant frequencies, impacting overall filter performance. Understanding these relationships is crucial for accurately identifying filter types and their functions.
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By looking at the components in an AC filter how can you determine what type it is based on the following information?
The impedance of a capacitor at very high frequencies is low
The impedance of a capacitor at very low frequencies is high.
Inductors have a direct relationship with frequency
The impedance of an inductor at very high frequencies is high
The impedance of an inductor at very low frequencies is low
The impedance of a resistor stays constant
A series resonant circuit at the resonant frequency is low impedance.
A parallel resonant circuit at the resonant frequency is a High impedance

This has been causing be some problems and I would appreciate some help.
Thank you.
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You can approximate these elements as either shorts or open circuits, depending on how the impedance behaves at high or low frequencies. If you replace them with shorts or opens as appropriate, you can see if the filter produces unity gain or zero gain.
 
How do you know which functions as a short and which as an open? Your explanation was not detailed enough for me to understand. What happens if a resistor is closest to the source?
 
Petrucciowns said:
How do you know which functions as a short and which as an open? Your explanation was not detailed enough for me to understand. What happens if a resistor is closest to the source?

Re-write the equations here that I posted in your other thread for the Z(f) for R, L, C. Then set f=0 to see what the impedance Z is at DC. Then set f=big to see what the impedance Z is at very high frequencies. That should get you going again.
 
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