I had to buy a new water heater and headed to the neighbourhood electronic appliances store. The salesperson patiently showed me a few models. When asked about the wattage of the heater, the reply was “two hundred and thirty, sir”.
I did not ask any other question.
This has been quite a common experience, at least for me. But why are volts so easy to confuse with watts? These are two different terms with different meanings for two different… entities.
Welcome (back after a long time) to the oversimplification of the basic units of electric current.
What is an electric current? Or simply, a current? A current is “a body of water or air moving in a definite direction”, as per the Oxford dictionaries. An electric current, then, is a collection of electrons moving in a definite direction.
Which direction?
High to low. Simple. Water moves from a higher altitude to a lower altitude. Air moves from a position of higher pressure to that of lower pressure. Similarly, electric current moves from a position of a higher “potential” to that of lower potential.
But what is “potential”, then?
Again, literally speaking, “potential” is the ability to do something. (He’s got the potential to lead the team.) Electrical potential means the ability of a thing to create a flow of electrons. Like water or air, electrons flow from a position of higher electric potential to that of lower potential. And the difference between these two “potentials” is called the… wait for it… “potential difference”!!!
Still with me? Onwards, then.
So, we saw what an electric current is. We saw why an electric current flows - electric potential difference. Now let’s see about power. Electric power, that is. Yet again, literally speaking, “power” is what makes something… move or stop; or go faster or slower; or create heat or reduce it. Think of a weightlifter. The more power s/he has, the more weight they can lift. Same with electricity. The more electric power, the higher the output of the device in whatever function it is supposed to do.
What’s a wattage, then? Or is it voltage?
If you were to carry a child’s school bag, then you probably wouldn’t find it heavy. But the child might. So how do we check who is right? By introducing a “unit of measurement”. Weight is measured in grams. Or kilograms. So the bag has a weight of some kilograms. “Some” kilograms is light for an adult but heavy for a child. And since the unit of measurement is universal, an adult or a child on the one side of the planet or the other can easily understand how heavy the bag is.
Similarly, wattage, voltage and ampere are standard units of measurement for electrical power, electrical potential difference and electrical current. Just as a higher number of kilograms indicates a heavier item, a higher voltage indicates a higher electrical potential - a higher capability of the device to make electrons move through it. And a higher current means a larger number of electrons flowing through the device. And a higher wattage means more electric power.
In my case, the higher the power of the water heater, the faster it heats the water.
That reminds me. I don’t think there’s a 230-watt heater built for residential uses.
But what is the connection between power and potential and current? Or wattage and voltage and amperage? Yeah, I know you know the formula. Not that. What’s the connection? Or, alternatively, how is this love triangle easily understood?
Imagine watering a pot of plant. Or pouring water into an empty bucket, if you want. Doesn’t matter. Standing next to it, pouring water doesn’t harm the pot or the bucket. Doing the same from the first floor might cause the pot/bucket to wobble and spill the water, let us say. From the third floor, watering it might make the pot/bucket fall. Top of the building? The poor thing’s going to crack.
Rewind. This time, you are standing next to it but you use a pipe from the fire services. With a very low setting of the water pressure, you can fill the pot, no worries. But as you increase the pressure, you still end up cracking the pot. Bucket. Whichever.
In other words, in both cases, you’ve ended up with a lot of power. So in terms of electrical devices, you can have a higher power by increasing the voltage (going higher up the building) or by increasing the current (increase the water pressure). Or both. But usually, the voltage is standard at approximately 230 volts in India. Let’s get into why that is in another post. So when a particular electrical device is more powerful than another, it effectively has the ability to allow more electrons to pass through it at 230V.
And the next time you go shopping for electronics, be sure to ask them what the wattage is. And if they say 230 watts for every device you ask them, show them this post.
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