In order to understand the basics of electricity, it is useful to first understand atoms.
Atoms are small particles that make up all matter. Inside the atom are even smaller objects called electrons, protons, and neutrons. Electrons have a negative charge (-) and protons have a positive charge (+). The protons and neutrons stick together in the center of the atom, called the nucleus. The electrons spin fast around the outside. The positive charge of the protons keeps the electrons from flying off and leaving the atom. In some elements, there are electrons on the outside of the atom that, when a force is applied, can become loose and move to another atom. When a bunch of atoms is together and electrons are moving from one atom to the other in the same direction, this is called electricity. Electricity is the “flow” of electrons. Think of what happens when you rub a balloon against your hair or scuff your shoes on the carpet on a dry day and then, touch a doorknob.
Ohm’s Law is a fundamental law in the field of electricity. It was discovered by George Ohm, and named after him. Ohm’s Law provides the relationship between current, voltage, and resistance. It states that the voltage across any resistance is equal to current times the resistance.
V = I × R
You can also find the current and resistance from Ohm’s law
I = V/R and R = V/I
Some related terms
We can make electricity by creating an electric current which consists of:
1. Power source – could be a battery or wall outlet.
2. Conductor – The wires that carry the electricity from place to place.
3. Load – what the electricity is powering, like the light bulb, air conditioner.
4. Switch – it connects the circuit together to start the electricity flowing.
Voltage is an electrical pressure, which forces the electric charges (electrons) to move in an electrical circuit. It is measured in volts, abbreviated as V. It is the measurement of the work required to move from unit between two points.
Electric current is the number of electrons flowing through a point in a circuit. It is measured in the amperes, sometimes called “amps”. It is denoted by the letter “I”.
Resistance, as the name suggests, provides resistance to the electrical current. It always tries to stop the current from flowing. Every material around the world has resistance to electric current. It is measured in Ohms.
Some materials have very small resistance; they are called conductors; while, other materials have very high resistance, and are called insulators. We use the conductors in the circuit for electric current to pass easily.
Resistance depends on the structure of the material:
There are two types of current that flow in a circuit – one is called DC (Direct Current) and the other is AC (Alternating Current).
DC – Direct Current
Direct current is the flow of electrons in one direction. Although, the magnitude of the current can decrease or increase it will always flow in one direction in a circuit. Batteries and chargers produce DC.
AC – Alternating Current
The alternating current doesn’t flow in one direction in a circuit. Instead, it changes its polarity (direction) constantly. The rate of changing polarity is called the frequency of AC. We all use AC current in our homes with 50 to 60 Hertz frequency. AC is often converted into DC by the chargers to charge your laptop and smart phone’s battery.
When electricity is at rest, it is called static electricity. It refers to the electric charges that build upon the surface of materials or substances. These so-called static charges remain until they are grounded, or discharged.
Static electricity is generated by friction, or sudden contact – for instance, rubbing two materials against each other. Ordinarily, atoms are ‘uncharged’. These are considered neutral substances, but they can lose or gain electrons through friction.
The rubbing procedure can cause the atoms of particular substances to lose their electrons. This loss of electrons will make the substance or material become positively charged. The excess protons caused the substance to have a positive charge. Conversely, the substance that gains the electrons is said to be negatively charged.
Current electricity, on the other hand, is a phenomenon of moving electrons in a particular path, or direction, such as a stream of them flowing through conducting materials. Current electricity can come from various sources. The most commonly used source of current electricity is batteries. These batteries rely on the chemical reactions within them to produce electricity.
Current electricity, in huge amounts, is typically brought about by generators. Power plants have many of these to produce enormous quantities of current electricity. The phenomenon is usually controlled, and requires a flow of electrons along a path, which is fittingly called the ‘electric current’.
