Resistors ...... For mechanical and electrical engineers

in #power6 years ago


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  • Resistance, according to Engineering dictionary by John Bird, is the ratio of the potential of an electric current applied to a given conductor to the current intensity value. Resistors can therefore be said to be the opposition to the flow of electric current.
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    In other words, it is a device or material that offers resistance to the free flow of electrons in an electric circuit. I am now going to relate it to ohms law to make it more understandable.
            Ohms law states,
                         V = IR
    Ohm is the unit of Resistance. It's reciprocal is Conductance.
    Let's run through some examples to make you see its theoretical application.
    Example 1
    Find the resistance of a coil which draws current of 50mA from a 120V supply
    Using formula,
    V= IR
    Making R subject of the formula
    R = V/I
    R = 120/50*10^-3
    R = 2.4k ohms
    Example 2
    Find the resistance of a material with conductance of 0.02 ohm-1
    Remember conductance is the reciprocal of resistance
    G=1/R
    Now make R subject of formula. I am going to show you two methods of doing this:
    1. Cross multiplication:
    G =1/R
    Cross multiply
    GR = 1
    Divide both sides by G
    R=1/G
    2. Inversion method
    G=1/R
    Invert both sides
    1/G = R
    Therefore,
    R = 1/G
    R = 1/0.02
    R = 50 ohms
    That's all for the post of today. In my next post, I will show you the different types of resistors there is and give credits to sites where photos were gotten from. I am also going to teach you all about colour coding.

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    You know about engineering?? You really are very good sir

    Thanks so much dear