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OHM'S LAW

Ohm's law states that current in a circuit is directly proportional to the resistance.  This means that: 

As the voltage applied to a circuit increases, the current also increases by a proportional amount.  Likewise, if the voltage applied to a circuit decreases, the current also decreases, the current also decreases. (if the resistance is held constant)

As the resistance in a circuit increases, the current decreases by a proportional amount.  Similarly, if the resistance in a circuit decreases, the current will increase. (if the voltage is held constant).

It takes one volt to cause one amp of current to flow through one ohm of resistance.

It is important to remember Kerchoff's law.  Kerchoff's law simply stated says that the sum of all voltage drops in a circuit must equal source voltage.

I find relating the above statement easier to understand if we equate the Law with a garden hose as follows:  Consider the flow of water volume to be current, and the pressure of the water to be voltage.  As we place our thumb over the end of the running hose pressure is increased (resistance from our thumb increased pressure or voltage) and flow from the hose is decreased (resistance is increased current is decreased).  If we release our thumb from the hose volume is increased while pressure is decreased (voltage is decreased with less resistance, and current or flow is increased with the absence of resistance).

Here is a chart to help calculate ohm's law  CHART

Here is a very helpful triangle  TRIANGLE

 

 

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Last modified: Wednesday March 21, 2001.
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