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ASVAB · Components and Devices

What is the main purpose of a transformer?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

To increase or decrease AC voltage

  1. A To store charge
  2. B To convert AC to DC
  3. C To measure current
  4. D To increase or decrease AC voltage

Why this is the answer

A transformer increases (steps up) or decreases (steps down) alternating-current voltage using two coils of wire wound around a shared iron core. The ratio of turns between the primary and secondary coils determines how much the voltage changes. Transformers work only with AC because they rely on a changing magnetic field. They are essential to the power grid, stepping voltage up for efficient long-distance transmission and down to safe levels for homes. Note a transformer changes voltage but does not convert AC to DC (that is a rectifier's job, using diodes).
Source: ASVAB Electronics Information — Transformers

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About this topic: Components and Devices

Components and devices questions cover what resistors, capacitors, inductors, diodes, transistors, transformers, fuses and switches do, and their schematic symbols. Recognising a symbol and naming its job is most of the section. This is one of 19 Electronics Information questions on components and devices, each with a full explanation on a single study page.

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