Conventional Current

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Conventional Current
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When we speak of the current flowing in a
circuit, we mean the direction positive charge
would flow.
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Important Current is not a vector, its a
scalar!!!!
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Important In any single circuit, the current at
any instant is the same at one point as at any
other point!!! This follows from the conservation
of electric charge.
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Ohms Law Resistance and Resistors
IV
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Definition of Resistance
IV/R
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Ohms Law
The current through a metal conductor is
proportional to the applied voltage.
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Resistivity
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Conceptual Example Stretching Changes Resistance
A wire of resistance R is stretched uniformly
until it is twice its original length. What
happens to its resistance?
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Effect of Temperature
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a temperature coefficient of resistivity is
positive for metals and negative for
semiconductors.
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Superconductivity