Let's Explore Electricity!

Electric Circuit

VOLTAGE AND CURRENT

Voltage ( sometimes called electrical tension ) is the electric force that causes the movement of electric charge (electrons) through a conductor. The electrons move from one atom to another.

To understand what is the voltage, it is useful to make an analogy with water.

Look at the picture ( left side ). It is water flowing in a garden hose. You should Think of electricity flowing in a cable in the same way as the water flowing in the hose. In a electrical circuit, the voltage causing the movement of electrons can be considered as the water pressure at the faucet, which causes the water to flow.

Increase the pressure at the hydrant, then, more water would flow in the hose. Similarly, Increase Voltage or electrical pressure, then, more electrons would flow in the cable.

A volt is the measure of electric pressure. Voltage is usually supplied by a generator or a battery.

Electricians use the letter "V", for Volts.

Current is "electrons in motion". It measures the number of electrons that can flow through a conductor. Electrical current is measured in amperes. To make a comparison with water, Amperes is like the number of liters of water flowing through a pipe per second. The scientific symbol for amps is the letter "I".

But, When current flows through a conductor it creates heat because of resistance.

Resistance is the opposition that a material offers to the flow of electrons.

Let´s go ahead. click on the next link to know a bit more about Conductors and Insulators

You may notice that a cord ( wire ) from an appliance may feel hot after running for some minutes. That is the amperage ( electrons moving along the cord ). The more electrons moving the more heat is produced in the cord. When a wire carries too many amps for its section, it becomes "overloaded" and the insulation ( the plastic ) can melt and produce a fire ( Most frequently reason for star a fire in homes ). That's why it is very important to use the correct cross-section.

Smaller section and longer wires have more resistance than wider section and shorter wires because the electrons has a "tighter" space to move through.

The measurement of resistance is called ohms, and the scientific symbol is the letter "R".

Definitions:

Appliance: An electrical device designed to perform a specific function, such as a Dishwasher, for household use. Examples of Appliance are: Air conditioning , Clothes dryer,
Vacuum cleaner, Computer, Microwave oven, Oven or Refrigerator.

Section. When we talk about section, we mean a cross section. So, it is a cut through something (a cable) at an angle perpendicular to its axis ( 90º) in order to measure its area. Another example of cross section is a cross section of a tree that shows its growth rings and tells us its history ( age, climate, illness, etc ). Do you remember?