Diodes & Resistance: Understanding Forward/Backward Flow

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Diodes exhibit low resistance when conducting current in the forward direction and high resistance when blocking current in the reverse direction. While some sources claim that diodes allow current to flow in one direction only, it's important to note that high resistance does not equate to zero current. The ideal diode is characterized by zero resistance in the forward direction and infinite resistance in the reverse direction, but real diodes can only approximate these properties. Understanding the I-V characteristics of diodes is crucial for grasping their functionality. Accurate knowledge of these principles is essential for effective electronic circuit design.
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I was learning about how diodes work , I read on some sites that diodes have a very low resistance in forward and very big resistance on backward. I read on other sites that diodes allow current in one direction only and no current in the other . So which is right , they 're not the same thing ( big resistance = small current and not no current at all )
 
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The ideal diode would have zero resistance in the forward direction and infinite resistance in the backward direction. Since diodes are fabricated from real materials, these ideal resistance properties can only be closely approximated.

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

This article shows the I-V characteristics of a typical p-n junction diode (Figure 5).
 
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