What is diode small signal resistance?

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Discussion Overview

The discussion revolves around the concept of diode small signal resistance, also referred to as dynamic resistance. Participants explore its definition, calculation, and significance in the context of diode behavior in electronic circuits.

Discussion Character

  • Technical explanation, Conceptual clarification

Main Points Raised

  • Some participants refer to small signal resistance as dynamic resistance, defined as the derivative of voltage with respect to current at a specific operational point on the voltage-current (V-I) curve.
  • One participant explains that while the V-I graph for a resistor is linear, the graph for a diode is nonlinear, indicating that the slope (and thus resistance) varies depending on the point on the curve.
  • The small signal resistance is described as applicable only for small deviations from the bias or DC operating point, emphasizing its conditional nature.

Areas of Agreement / Disagreement

Participants present different aspects of the small signal resistance concept, but there is no explicit consensus on a single definition or interpretation. The discussion remains open with varying viewpoints.

Contextual Notes

Participants do not address potential limitations or assumptions in their explanations, such as the specific conditions under which the small signal resistance is valid or the mathematical derivation of the derivative.

Anik Paul
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I'm not realising this thing.
 
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Hello, in my opinion it's also called dynamic resistance. It's derivative at given operational point on VA curve, dV/dI.
 
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If you plot a V vs I graph for a resistor you get a straight line. The slope is the resistance.

Same graph for a diode is a curve so the slope (resistance) isn't constant. The small signal resistance is the slope at a particular point on the graph. That point is usually called bias or DC operating point. The resistance is only valid for small deviations from the bias point hence why its called the small signal resistance.
 
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Likes   Reactions: GrahamN-UK, Anik Paul and Averagesupernova

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