How does a capacitor allow AC to pass through it but stop DC?

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A capacitor allows AC to pass while blocking DC due to its frequency-dependent impedance, which is infinite at DC and decreases with increasing frequency. In clamping circuits, this behavior is utilized to create high-pass filters, preventing low frequencies and DC from passing through. The configuration effectively allows high-frequency currents to flow through to the resistor. Understanding the current-voltage relationship of capacitors is essential for grasping this concept. This mechanism is crucial in various electronic applications.
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clamping circuits...mechansim

See i have a problem regarding clamping circuits:
1.what do we mean when we say that "capacitor allows ac to pass through it but stops dc"
2.please see the attachement
 

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mj345 said:
See i have a problem regarding clamping circuits:
1.what do we mean when we say that "capacitor allows ac to pass through it but stops dc"
2.please see the attachement

The impedance of inductors and capacitors is frequency-dependent. For capacitors, the impedance is inversely proportional to frequency. So the impedance of a capacitor is infinite at DC, and zero at very high frequencies. The configuration in your diagram is a high pass filter, with low frequencies and DC current not making it through the capacitor, and high frequency currents passing through the capacitor to the resistor.

See the current-voltage relation information for capacitors here, for example:

http://en.wikipedia.org/wiki/Capacitor

.
 
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