Electric Lingo: What does it mean?
The terminologies describing the field of electricity are demystified and given practical explanations.
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First published: March 29, 2008
Because you are reading this (meaning you have access to a computer and are online), I am sure you have an idea about what electricity is. Most of us do. According to Wikipidea, electricity (from New Latin ēlectricus, "amber-like") is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. For some folks, however, the terminologies found on the manufacturer's plates on their equipment is sometimes a mystery. Yes, those plates that give the power rating, design voltage, serial number, etc of the equipment. Here, I will attempt to make these terms a little more palatable to those who prefer not to dwell on what the terms mean but in practice have to understand what they are about.
Electricity flows through a path (the most common type of paths are wires) when the source (for example a power generating plant) has more kinetically agitated electrons (units of atoms that carry a charge) than the destination (for example your flat iron). The agitated electrons at the source escape into the path and come out at the source. At the destination, they do useful work like heating up your flat iron and lose their energy (agitation) in this way. When you turn your iron off, you block their path so they do not get to the destination. So, what is all this voltages, amps and watts stuff?
Voltage. If you were to jump on to a toboggan and slide down a hill (called playing 'goggolo' in some parts of Uganda), you would naturally stop as soon as you reached the bottom of the hill. We all know that when you are at the top of this hill, you will always fall or roll down the hill if not stopped. In fact, if you have a rope tying you to a child at the bottom (but on the other side) of the hill, this child will be pulled up the hill as you head down. This is because you are heavier than the child is. The heavier you are than the child is, the easier it will be for you to pull the child up.
This difference in weight is the equivalent of voltage in electricity. When a source of electricity is at a higher voltage (has more agitated electrons bent on escaping) than the destination (electrical equipment), the electrons, in a bid to escape, migrate through the path (usually a wire) to the destination. The more agitated electrons at the source, the higher the voltage (difference in agitation) and vice versa. I hope you are getting my drift. The higher the voltage (or difference in weight between you and the child), the bigger the bang when things go wrong! Voltage is usually measured in units called volts (V).
Current. We all agree that tobogganing down a steep hill is faster than down a gentle slope. The steeper slope means that you meet less resistance on your trip down and unless some form of brakes are applied, you will slide faster with a steeper slope. This means less time for you to get to the bottom and more runs in a given period.
In electrical terms, the faster the electrons flow through a path from the source to the destination, the higher the (current). The speed with which electrons can flow depends a lot on the nature of the material through which they are flowing. They flow faster through most metallic objects than they do through water, for example. Current is often measured in units called amps (A).
Resistance. If, while going down the hill on a toboggan, you decided to stick your feet out into the ground or snow, you would certainly slow down. What you would be doing in effect, is increasing the resistance to the forces that are pulling you downhill.
Any impediment to the flow of electrons between a source and destination is called resistance. The degree of impediment depends mostly on the nature and dimensions of the material from which the path of the electrons is made. Copper, steel and other metallic materials are the equivalent of an autobahn in Germany while dry wood is the equivalent of the current state of some 'highways' in Uganda – almost impassable. The less resistance offered by the path, the faster the electrons flow through it. Resistance is usually given in units called ohms (Ω).
Power. This is probably the most commonly used term when referring to the performance of electrical equipment. Power refers to the relative ability of a piece of electrical equipment to do work. The more power, the stronger. Just like you and that child on the other end of the rope. If the child was three years old and the two of you engaged in a tug-of-war, you would win because your muscles are more powerful. Similarly, a 14'' TV set consumes much less power than a 42" set. While both TV sets may use the same voltage, the current (number of electrons) flowing through the 42" set is higher and therefore does more work. Power is usually quoted in watts (W).
Energy. When your electricity bill comes, it shows how much energy your electrical equipment consumed and therefore how much you owe the supplying company. To arrive at this, the meter knows how much power your equipment takes, for how long you run it and tots up the units. The guys in the supplying company's accounts office multiply this sum with the cost per unit, add taxes and send you the bill.
We shall chat about the various sources of electricity, the results of its misuse and where we would be without it on another occasion. For now, just be sure that the longer you leave your hot shower tap open, the longer your bill is going to come.
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First published: March 29, 2008