Electrifying, My Dear

Thought for the day: If it weren't for electricity, we'd all be watching television by candlelight. [George Gobel]

[THEME: Amateur radio]

Amateur radio operators are expected to learn some fundamentals of basic electronics, and one of the things we learn about is OHM'S LAW, which expresses the relationship between voltage, current, and resistance.








Voltage (E) refers to the amount of electromotive force (EMF) applied to a circuit, and can be compared to water pressure going through a pipe. The more voltage, (or pressure) the more electrons (or water) flowing. Voltage is measured in volts.

Current (I) measures the number of electrons flowing. No, you can't count them as they flow past any more than you can count the individual drops of water in a waterfall, but just as water is measured in quantities such as gallons, the electron flow is measured in amperes. One ampere is equal to 6.24 x 10 to the eighteenth power. (That'd be a LOT of counting!)






Resistance (R) is just what it sounds like. If you put a blob of hair or sponge into a water pipe, it'll block the flow. In the same way, resistors resist the flow of electrons, and limit the amount of current flowing through a circuit. Resistance is measured in ohms.

Here's a bunch of different resistors. See those color bands on them? Each color represents a different number, and in simplest terms, the numbers express the resistor's value.








So what does Ohm's Law tell us? That within a circuit, voltage equals current times resistance. E=IR.

                                                               So, there ya have it.