Understanding the concept of electronics requires a simple understanding of what electricity is. Electricity may be defined as the flow of electric charge, a movement of electrons. Electrons create charge, which can be utilized to do work. A light bulb lights up when it harnesses the movement of electrons. Other electric devices operate using the same force – movement of electrons.
Here are a few basic concepts related to understanding electricity and electronics:
- Electrical charge – It is a property of a unit of matter that reveals the extent to which the number of protons exceeds or is less than the number of electrons. Electrical charge is either positive or negative. Like charges repel each other while unlike charges attract each other. A negatively charged object has an excess of electrons, otherwise it is either uncharged or positively charged. The international standard (SI) unit of electrical charge is the coulomb (C), or ampere-hour (Ah) in electrical engineering.
- Voltage – Also known as electric pressure, electric tension, or electric potential difference, voltage is the indicator of the difference between electric potential energy between two points, per unit of electric charge. It can be caused by electrical current passing through a magnetic field, static electric field, time-varying magnetic field, or a combination of any of those three. A voltmeter measures voltage between two points in a system.
- Current – This is the movement of the electric charge. Electrons moving through a wire in an electric circuit carry charge. Electric current can also be carried by ions in the electrolyte, and by both electrons and ions in plasma. Ammeter is the device that measures electric current. Electric current creates light in the incandescent light bulb by means of Joule heating. It also creates magnetic fields in motors, generators, and inductors.
- Resistance – This is an electrical quantity that represents how a device diminishes the electric current flowing through it. It is measured in units of ohms. The inverse of resistance is conductance, which is the ease with which the electric current passes.
Ohm’s Law states that currents that pass through a conductor between two points are directly proportional to the voltage across two points. Ohm’s law is a predictor of the relationship between potential difference, current, and resistance. Understanding Ohm’s law gives us a basic concept of how electricity works.