7.2 Dynamic resistance

  Semi-conductor Devices and Electronics

    1.0 Introduction
    2.0 Types of semiconductor
    3.0 Mass action law
    4.0 Electrical conductivity in semiconductor
    5.0 $p-n$ junction
    6.0 Breakdown voltage
    7.0 $I-V$ characteristics of a $p-n$ junction
    8.0 Rectifier
    9.0 Light emitting diode (LED)
    10.0 Zener diode
    11.0 Transistor
    12.0 Boolean identities
    13.0 Logic gates
    14.0 De Morgan's theorem

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7.2 Dynamic resistanceIt is defined as the ratio of a small change in voltage $\left( {\Delta V} \right)$ applied across the $p-n$ junction to a small change in current $\left( {\Delta I} \right)$ through the junction.
$${r_d} = \frac{{\Delta V}}{{\Delta I}}$$