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I'm confused about ohms law

Discussion in 'General Electronics Chat' started by suhasm, Apr 27, 2009.

  1. Ratchit

    Ratchit Well-Known Member

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    Mikebits,

    No, a diode does not obey Ohm's law. Ohm's law is a property of a material, specifically resistive linearity with respect to current. Since its voltage vs. current plot is not linear, it is not ohmic with respect to Ohm's law. A diode and everything else does have a resistance or impedance defined by V=IR or V=IZ at all currents and voltages that do not destroy it. Again, V=IR is not Ohm's law, is is the definition of resistance or impedance.

    With respect to 'ohmic', depending on the context, it means whether something follows Ohm's law (resistive linearity) or whether something has a resistance like a switch contact. I believe these two contextual meanings cause confusion.

    Ratchit
     

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