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ASVAB · Components and Devices

What is the primary function 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 increase or decrease AC voltage
  2. B To convert AC to DC
  3. C To store charge
  4. D To measure current

Why this is the answer

A TRANSFORMER increases ('step-up') or decreases ('step-down') AC VOLTAGE using electromagnetic induction between two coils (primary and secondary windings). ASVAB Electronics Information tests components. The voltage change depends on the ratio of coil turns: more turns on the secondary = step-up (higher voltage); fewer = step-down (lower voltage). Transformers work only with AC (changing current creates the changing magnetic field needed). Used in power distribution (high voltage for transmission, stepped down for homes) and adapters. Knowing the transformer changes AC voltage is commonly tested.
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.

New to this exam? Our ASVAB exam guide explains the format, scoring, and how to prepare.

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