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All about Electrical Resistors


Resistors

  • Bilateral, Passive, Linear Element
  • Resistors oppose the flow of current flowing through it.
  • Resistors obey Ohm's Law

    i.e. I ∝ v

  • Resistors dissipates energy in the form of Heat

    S = σ + jω Complex Frequency

    σ = Attenuation Constant

    ω = Angular friquency

    Power Loss in resistor (P)

    P = V &times I = I2 &times R = V2 ÷ R

  • Energy dissipated in Resistors as heat in Joules

    or Simply

    ER = I2 &times R &times t = ( V2&times t ÷ R ) = ( V &times I &times t )

  • Change in Resistance due to change in dimension

    l = length of conductor

    A = Cross Sectional Area of the conductor

    ρ = Resistivity of condutor materil

  • Change in Resistace due to change in temperature

    Let…

    Rt = Resistance of material at temperature t.

    R0 = Resistance of material at 0° temperature.

    αt = Temperature Coefficient of resistance at temperature t.

    Then…

    Rt = R0(1+α0t)

    R0 = Rt(1-αtt)

    Rt2 = Rt1{1+αt1(t2-t1)}

    αt = α0 / (1 + α0 t)

    αt2 = αt1 / {1 + αt1 (t2 - t1)}

    α0 = Slop of temperature vs Resistance plot curve / R0

    αt = Slop of temperature vs Resistance plot curve / Rt

    α0R0 = αtRt

    αt1Rt1 = αt2Rt2

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