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Basic Principles
This chapter is a simple introduction to electricity, what it is and how it is produced. You will learn the standard units and symbols used in electronics and be shown the basic components.
Introduction
Electrical Terms
Primary Cells
Secondary Cells
Electrical Units
Insulators and Conductors
Circuit Components
Standard Symbols
Introduction
Developments in electronics over the years have had a profound effect on the way we lead our lives. We are so surrounded by electronic gadgets that if electricity had never been discovered it’s almost impossible to imagine what our lives would now be like.
The result of numerous electrical discoveries and developments over the centuries means that we have today become more technologically aware than ever. Consequently, you will be reading this book because you want to learn more about electronics, components, and circuits.
To understand all of this, first you have to learn, in simple terms, a little bit about electricity and how it works because that is the power behind electronics – this is what this chapter shows you.
The invisible force
Electricity was not invented but discovered. It is a form of energy that occurs in nature and so was always there, but we couldn’t easily see it other than, for example, during a lightning storm. It was realized quite quickly that there existed some sort of strong, invisible energy or force that deserved investigating further.
Centuries of experimenting and development has given us the basic electrical laws and principles that now allow us to not only understand electricity, but to use it to create electronic circuits and make electricity work for us.
Here are three of those credited with some of the early work:
•Benjamin Franklin – established the connection between lightning and electricity.
•Alessandro Volta – discovered that certain chemical reactions could produce electricity, and created a crude electric battery.
•Michael Faraday – discovered a mechanical method of generating electricity when he created the electric dynamo.
So, electricity wasn’t discovered by just one person. The concept of an invisible energy had been known about for thousands of years, but it was a combination of the individual efforts of many great minds that has given us the understanding we have today.
The world has become totally reliant on electricity as a prime energy source. Just think where we would be today if it had never been discovered.
Although electricity can be fun to experiment with, it can also be dangerous when working with high voltages. A mistake could be fatal if the correct precautions are ignored, so always take note of any safety advice or warnings.
Electrical Terms
Energy can take many forms; like heat energy, for example. Electricity is simply the name given to electrical energy and, as with heat, there needs to be a difference in potential for it to travel from one point to another. But ...
