Overview of Electronics
Franklin described electricity or "Galvinism" as
My name is James Lincoln. I'm a physics teacher here for About.com.I'll begin the story with Benjamin Franklin and Luigi Galvani. Franklin described electricity or "Galvinism" as a fluid that flowed easily in metals. For example, some early experiments involved frog legs being electrified and kicking over a long distance through a metal. Or in Franklin's house, a metal lightning rod would come through his roof into his study and ring a little bell anytime lightning was in the area. Franklin also described two types of charge, positive and negative. And he imagined that when something was charged it was filled up with a positive fluid. These days, we now know that it is the negative charges that flow. These charges are called electrons. Two different metals can produce a continuous flow of charge because one metal attracts electrons more than the other. You can connect them and supply the charge with any chemical liquid or paste. This unit cell is called a battery. And the pressure that the battery pushes through is called the voltage or tension or potential. But it's mostly called the voltage. Voltage is named after the person who invented the battery, Allessandro Volta. Of course, he would never call it voltage; he called it tension. The flow of electricity is called electric current and it can be useful. But only if the circuit is complete. That is, the charges need to flow all the way from the negative side back to the positive side. In conclusion, the basic circuit came out of the research of Franklin, Galvani and Volta. And we wouldn't have any electronics today if it weren't for these early experiments. I'm James Lincoln for About.com. Thanks for watching.