Transformers are a common sight for most of us, even if we don’t know what they are. Not only do we frequently pass them as part of the electrical power grid, but they are commonly employed inside chargers for phones, consoles, and other household electronics. In this article, I will give you a reasonably brief explanation of this common electrical device, how it works, and why we need them.
In order to understand electrical transformers, we must first have a basic understanding of how electromagnetic induction works. To put it simply, a magnetic field can induce an electrical voltage in an electrical conductor. This means that if you were to take something with a magnetic field (such as a magnet), and cause the magnetic field to interact with a conductor, you could induce a current. A helpful way to visualize this is to imagine your conductor as a tube of water, and your electromagnetic field as a turbine blade. If the blade moves back and forth, the electrons in the conductor will do the same. If you spin it, they will flow, creating an electric voltage.
The same will happen in reverse. If you have an electric conductor, and you allow a current to flow through it, a magnetic field will be generated around the conductor. This is what allows us to build electromagnets. In other words, flowing electricity interacts with and creates magnetic fields. If you are having a hard time visualizing it, there are plenty of animations of this principle for free available on popular video sharing sites.
High vs Low Voltage
Now that you understand how electromagnetic induction works at a basic level, I will explain why we need transformers and what they do. Voltage is the difference in charge between two points on a circuit. A high voltage will mean there is a lot of energy, as electrons seek to flow between the two points. When looking to transport power over long distances, it is generally best to use high voltages. Because of the way energy is lost in an electrical system over time, when transmitting energy long distances, a high voltage but low current will increase your efficiency drastically. As producing electricity is expensive, and we consume incredible amounts of it, it is in the interest of our electrical engineers to create systems which can decrease the amount of power lost in transit.
However, it is often the case that we do not want to use incredibly high voltages for daily use. There are several reasons for this. First, high voltages can be incredibly dangerous. High voltage line must be insulated and protected incredibly well. If you come into contact with a high voltage line, you could experience an electrical discharge sufficient to cause lethal damage. This is not just dangerous because it is likely to cause electric shock, but these high voltages can also lead to other dangers associated with electrical discharge, such as increased risk of fire or other damage to infrastructure.
Additionally, high voltages are overkill for most household functions. When you want to hammer in a nail, you could use a sledgehammer, but you will likely tire quickly, and risk damaging the nail and its setting. Instead, using a smaller voltage can help you to more effectively and safely complete your task. This is where transformers come into play.
How to Change Voltage Using a Transformer
An electrical transformer takes advantage of the principle of electromagnetic induction to either step up or step down electrical power to higher or lower voltages. In an electrical transformer, electrical power is allowed to be in flux through a coil. If this coil is touching a conductor, which is connected to another coil, the electromagnetic field will cause a magnetic field to also be in flux. As a steady magnetic field will not induce a current, it is important that this electromagnetic field is in flux, going back and forth. Because of the way energy is conserved in the system, the arrangement of the coils will cause either a higher or lower voltage to exist in the secondary coil. So, we can use step up transformers to create high voltage wires which can transmit power long distances. Then, we can step it down to a level which is safer for distribution into houses. Finally, the chargers on electrical devices can step it down even further, to a voltage which is appropriate for the device in question. This is why it is important to always use a charger and system which is supplied by the manufacturer. If the charger is not appropriate or poorly manufactured, a surge of high voltage power could enter your device or system, causing damage or fire. So, the next time you plug something in to the wall, appreciate a simple invention which has changed the world: the electrical transformer.