Not all transformers are shape-changing giant robots; most are simple electronic components that help your world run smoothly. Transformers are everywhere from the charger you used last night for your mobile to the lines that distribute electricity from the mains to your house. They can be as large as a house or as small as your fingernail. While most laminated transformers are roughly square in shape, toroidal power transformers have been growing in popularity.
How Transformers Work
Transformers are one of the reasons for the widespread acceptance of alternating current as they make it easy to adjust voltages for different needs. The key to transformers is that a fluctuating electric current in one coil can create a fluctuating magnetic field, which can then induce a second fluctuating electric current in another coil. By changing the ratio of the number of windings in the two coils you can vary the relative voltage between the two circuits.
Standard transformers use a series of plates laminated together with a poor conductor separating each plate. The purpose of these laminations is to limit the losses caused by eddy currents in the core so that more of the energy goes to the secondary coil. It works, but is still relatively inefficient with some transformers taking up to ten per cent losses.
In comparison to laminated E-I transformers a toroidal transformer can cut losses by up to fifty per cent because the shape works with the magnetic field rather than against it. This helps allow toroidal models to be half the weight and size of their compatriots and reduces losses as well as hum, heat and vibration. Toroids are well suited for instrument and other uses where circuit isolation is at a premium.
The toroidal shape is also found in split core current transformers. Primarily for instrumentation, these transformers mount around a primary lead and then feed a meter that measures current flow. Split core models are often preferred because they can easily mount and come off without affecting the primary.