WHAT IT IS​

Electricity is measured in three basic units, namely voltage (V), current (I), and resistance (r). Voltage is measured in volts, current is measured in amps and resistance is measured in ohms.

A system of plumbing pipes may help understand these terms better. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is like the pipe size. The table below, known as the Ohms Law Wheel, illustrates how these terms relate:

Returning to the plumbing example, consider a tank of pressurized water connected to a hose that you are using to water the garden. If we increase the pressure in the tank, more water comes out of the hose. This is similar to that of an electrical system; increasing the voltage will make more current flow.

Similarly, if we increase the diameter of the hose and all of the fittings to the tank, this also makes more water come out of the hose. This is similar to decreasing the resistance in an electrical system, which increases the current flow. Resistance can be reduced by using better conductive material.

Electrical energy is measured in watts. In an electrical system, power (P) is equal to the voltage multiplied by the current. Here, the plumbing analogy still applies. For example, pointing a hose at a waterwheel can increase the power generated by the waterwheel in two ways: Increasing the water pressure will force more water hitting the waterwheel, thus turning the wheel faster. Or, increasing the flow rate will drop more water (and weight) on to the waterwheel, thus turning the wheel faster.

 

 

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References:

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​http://commons.wikimedia.org/wiki/File:Ohms_law_wheel_PURI.svg
http://science.howstuffworks.com/environmental/energy/question501.htm
http://electrical.about.com/od/panelsdistribution/f/How-Does-Electricity-Work.htm