What is an Electrical Current?
Author: John Published Under: Technology
Electricity is not a new invention, but at no other time in history has it been as inexpensive and easy to obtain as it is today in most western countries. An electric charge is made up of millions of electrons and this is one of the easiest ways to measure an electrical charge, although it is not the only way.
When counting the number of electrons in an electrical charge, you are describing its current. Current can be affected by many outside factors, such as insulation and the ability of the objects it is passing through to conduct electricity.
How Charges are Measured
There are two units that are used to describe an electrical charge. The simplest unit is found by counting the number of electrons, with each electron representing a single unit. This type of measurement is called an elementary charge or an elementary charge unit (ECU,) which can be negative or positive.
Since there are millions and millions of electrons at work, a larger unit of measurement, the coulomb is used.
One coulomb is equal to 6,240,000,000,000,000,000 ECU, which in scientific notation is 6.24x10^18.
Current
When particles that are charged move around, they create what is called an electrical current. In most cases the moving particles are electrons, but any object that is charged and moving creates a current.
Conductors
There are some objects that allow electrons to move very easily, while others basically do not allow them to move at all. An object that allows electrons to move is said to be an electrical conductor, with good conductors being materials that allow electrons to remain highly active.
At room temperature, silver is one of the best conductors around, but since silver is very expensive, copper and aluminum are usually used, which are also excellent conductors. Liquids, such as salt water and mercury, can also be conductors, although distilled water is a very poor conductor.
In concept, water flowing through a hose can be used to describe the flow of electrons through a conductor, but electrons do not actually move the same way as water would. They actually jump, however, from one nuclei to another, in an incredibly rapid fashion.
Insulators
Insulators are materials that do not allow electrons to easily pass through them. Insulators are usually used to control the way an electrical current flows or to prevent it from flowing into a specific area. Since insulators do not allow electrons to easily flow, they are considered poor conductors.
There are many common insulators and many gases preform extremely well as insulators. Wood that is dry, plastic, paper, and glass can also be used as insulators. Purified water can also be used, although if minerals are present in the water, than they will allow current to pass through them.
Some times matter that can be used as an insulator is classified as a dielectric.