Terms like ampere, volt, watt, and power are terms we might hear when the topic of electricity is being discussed. But though some of us may understand or remember clearly what they represent, the majority of folks are probably a little hazy. Electricity is something that is often taken for granted, but is an extremely important part of our lives.
One reason electricity might be taken for granted is because it cannot be seen. However, we probably don’t need to be reminded of its power, am I right? As complicated as it may seem, terminology exists to give us a better understanding of fields of a more complex nature. Electricity is no exception. In this article I will be outlining some terms used in household electricity and their meanings.
Voltage: The electromotive force or potential difference between 2 points on a conductor, expressed in volts; it represents the pressure that pushes the current through a conductor, where the amount of pressure is determined by the amount of voltage, or volts.
Ampere and Current: These terms are closely related in that the former is the SI (base) unit for the latter. The ampere is defined as an electric charge of one coulomb per second. So the term “amp” is simply short for ampere, and we now know that an ampere is the equivalent of one coulomb of electrical charge flowing through a given medium.
Coulomb: The charge transported by a steady current of one ampere in one second. Through the definition of the coulomb, the relationship between itself, charge, current, and ampere become clear.
Watt and Joule: The watt is the SI derived unit of power, defined as one joule per second. The joule is the SI derived unit of work, equal to the energy expended (or work done) by applying a force of one newton through a distance of one meter (1 newton meter), or in passing an electric current of one ampere through a resistance of one ohm for one second. This makes the watt a measurement of work per unit time.
So having familiarized ourselves with the above basic terminology, we can now move on to how they are applied to daily life. Appliances have their electrical requirements and specifications visible so people will know how much electricity they consume as well as what kind of current they use. With this knowledge people can then make an educated decision to purchase.
How Electricity Gets to Our Homes
Electricity is generated at large power plants and transmitted, often over significant distances, to supply power to the general public. In order for electricity to be transmitted efficiently over large distances, it must be “stepped up”, i.e., the voltage must be raised. Power losses in a conductor are a product of the square of the current and conductor resistance – meaning double current equals quadruple power loss.
Thus, power is stepped up prior to long-distance transmission, and then stepped down once it gets close to the load, or where it will be used. It will then enter commercial buildings, factories, and homes, often at varying voltages in accordance with their individual needs. Depending on country and region, you may have anywhere between 100 and 240 volts entering your home’s main breaker.
From there, electricity will be drawn to various parts of your home, wired so as to ensure all circuits are more or less being uniformly loaded, as well as ensuring that none are being overloaded. Breakers at the main circuit breaker are set to fall if and when circuits are overloaded, but it’s no fun when they’re constantly falling!
Electrical Symbols and Diagrams
We may at times see little diagrams and symbols on the backside of electrical appliances that we’re not familiar with. There are 2 types of current – alternating current (AC) and direct current (DC). Appliances that run on DC will typically have an adapter that converts AC into DC. These adapters will take the AC and not only “adapt” it to DC, but also “adapt” or lower the voltage to the specified amount.
Most appliances will have their wattage printed somewhere on the body itself or the adapter, but if not, it should definitely have the amps and volts displayed. By multiplying the amps and volts you can get an estimate of the maximum wattage that is used. You should note here that this wattage is typically the maximum wattage which means it will vary depending on factors such as volume and settings.
Dispelling the Myth that “Higher Voltage equals Lower Electricity Bills”
By definition, the more work an appliance does, the more power or wattage it’s going to need. Power is the product of the current and voltage, which means that by increasing the voltage you can significantly decrease the current, or amperage, and still get the same power. This is beneficial in that manufacturers can use thinner conductor material throughout the appliance as the current will be smaller.
However, although the current decreases, the power remains the same, which means your electric bill will also remain the same. So no, 200 volt appliances are not cheaper to run in comparison to 100 volt, but simply cheaper to manufacture. Again, power is the product of both voltage and current, which makes the power consumption, or wattage, the value produced when multiplying the amps (current) and volts (voltage).
How Does Wattage Affect Your Electricity Bill?
Obviously, the higher the wattage a given appliance has, the more “power” it will use, and thus, the more you will have to pay per unit time on your electricity bill. One thing to keep in mind though, is that high wattage is not the only thing to consider if you’re concerned about your monthly electricity bill. The amount of time you would use the appliance is equally as, if not more, important.
For example, microwaves, toasters, hair dryers, and electric ovens all have relatively high wattage. But there is a critical difference between the first 3 examples and the last one – the electric oven. You probably guessed it, but the first 3 examples are usually only used for a few minutes at a time maybe once or twice a day, whereas an electric oven can easily be used for a half-hour or an hour while baking those pies you love so much.
On the other side of the coin, relatively low-watt appliances such as fridges, kerosene heaters, coolers, and incandescent lights that might only use a 3rd or 4th of that power but run for long hours daily, possibly even 24/7, are the bigger contributers to your electric bill. However, there is a reason they run for long hours – they are important to the daily functioning of our lives.
Power companies typically use a standard billing measurement called kilowatt hour (kWh), and is equal to 1,000 watts of power used for a period of one hour. In this way it is clear that both wattage and elapsed time is important when calculating power consumption and cost. A proper balance is needed taking into consideration your needs, desires, and income.