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MY CART The Significance of Transformers
Your electrical power sources have a problem. Whether it be the power plant or a gas generator, the electricity they produce tends to be of high current and low voltage. These values are not optimal for distribution along power lines and will also need to be adjusted in order to be used for many household appliances. The voltages generated at the source need to be increased and decreased several times before they are usable for the average consumer.
If you happen to be charging your phone or laptop while reading this, you know that this problem has been solved to enable you to use these devices. The equipment responsible for mediating increases and decreases in voltage is the transformer. You might be most acutely aware of transformers when one supplying your neighborhood’s power grid has blown. Less obvious ones include those in the power adaptors for your laptop and smartphone, or the one in your microwave.
What are Transformers?
Learning more about how transformers work will help you know when you encounter them in your home. You may also find yourself in a situation where you need to go out and buy or rent a transformer to power your appliances.
Transformers manipulate voltage, a value that helps define electricity. Generators of electricity typically produce relatively low voltages (although much higher than what you would use at home) and relatively high currents. We can apply these to Ohm’s Law (voltage = current * resistance) to understand that voltage and current have an inverse relationship. Given a constant resistance, increasing one will decrease the other. Transformers manipulate this relationship to solve problems in distribution of electrical power.
If we were to take a look inside, transformers are made of three basic components. An insulated iron ring, a wire coiled several times around one side of the ring (the primary winding) and a separate wire coiled around the other side (the secondary winding). An electrical current from the power source flowing through the primary winding induces a magnetic field which magnetizes the iron ring. The secondary winding feels the pull of this magnetic field, inducing an electrical current.
The voltages in the primary and secondary windings will be different. This difference is changed by manipulating the number of coils in each of the windings. If the secondary winding has fewer coils than the primary, there will be a decrease in voltage (stepping down). If the secondary has more coils than the primary, there will be an increase in voltage (stepping up).
What is a Step-Down Transformer?
There are many different reasons you would need to decrease voltages to supply electrical appliances. For one, power lines carry high voltages and low currents in order to reduce waste while carrying electricity hundreds of miles. A step-down transformer decreases the voltage of electricity in the line carrying power to residences to the standard for household use.
If you’ve ever been overseas and needed to charge your phone, you may have needed to buy a special outlet adaptor. American and Canadian wall outlets typically carry voltages of 120 V, while European wall outlets use 220 V. The outlet adaptor is a step-down transformer that reduces voltage for use on North American-calibrated devices.