An electrical device consisting of a magnet with wires coming in and would around it on one side, then another set of wires wound around it on the other side. It allows isolation of one side to the other since the wires are not actually touching each other but it still allows (alternating) electrical current to pass. Depending on the ratio of the number of times the two different wires are wound around the magnets, it will also change the amount of voltage/wattage passed through it such as changing a microphone level signal to a line level signal. Power transformers step-up or step-down electricity that's then used to power other electrical devices at a different voltage.

Source: [http://www.allchurchsound.com/ACS/glossary/index.html Church Audio & Acoustics Glossary] [[Category: Acoustics]]