How Do Isolation Transformers Work?

Updated April 17, 2017

Every day, Americans use numerous electrical devices, from lamps and hairdryers to cell phone chargers and coffee makers. Each and every device is connected to the main voltage in the home. The mains voltage runs at 120 volts and has access to a great deal of current. This current poses great risk to humans, which requires a good deal of safety built into the circuit. This task is accomplished within the circuit in part by the isolation transformer.

Isolate the Circuit from the Mains

Isolation transformers are built typically with a 1 to 1 ratio. Five volts in is five volts out. The protection comes from the fact that the second coil is not connected to the first, which is connected to mains. As a result, touching a part of the circuit connected to the second coil will not result in a deadly shock. The design of the transformer depends upon the usage that the circuit will draw, typically resulting in larger and heavier transformers needed for higher current applications.

Protection for People and Circuits Alike

Isolation transformers are not just for isolating electronics from mains voltages. it is also useful for separating parts of a circuit so that power is transmitted while protecting sensitive electronics. Chips and sensitive electronics require a small voltage; anymore can destroy the chip. In contrast, motors, solenoids, relays and many other components require larger voltages. These circuits may need to interact, and the device that protects the more sensitive components is the isolation transformer.

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About the Author

James McIlhargey is currently attending the University of Texas as a doctoral candidate in physics. In addition to his studies, McIlhargey has quite a bit of experience in electronics, engineering and other science-related fields, which he uses to write online content for various websites.