Parts of a Charger

A plug-in phone charger and its cable, then the charger cut open.

Parts of a Charger

Name Date

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1 2 3 4 5 6 7 8
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Write the name of each numbered part.Answer key

  1. Prongs
  2. Case
  3. USB port
  4. USB cable
  5. Connectors
  6. Circuit board
  7. Capacitors
  8. Transformer

Drawn for this site on 2026-09-30 from plain shapes. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: the parts of a phone

All 8 parts on the diagram

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Outside 5

  1. Prongs They go into the wall outlet. They carry the mains power into the charger. Also called blades or pins.
  2. Case The case is the hard plastic shell. It holds the prongs and the port and closes in the electronics.
  3. USB port The USB port is the socket on the end of the charger. Low-voltage power leaves the charger here.
  4. USB cable It carries power from the charger to the phone or other device.
  5. Connectors A cable has a connector at each end. One goes into the charger and the other into the device.

Inside 3

  1. Circuit board It holds the electronic parts and joins them with thin copper tracks.
  2. Capacitors The capacitors smooth the power so that it flows evenly. The large ones in a charger are shaped like small cans.
  3. Transformer It passes power from the charger's high-voltage side to the low-voltage side. It is often the biggest part inside.

How this list was compiled: Every name was checked on 2026-09-30 against sources read that day; a name is kept only when two independent ones use it. (1) Wikipedia, text only: AC adapter, https://en.wikipedia.org/wiki/AC_adapter (an external power supply, often in a case like an AC plug; modern ones are switched-mode, with a transformer working at high frequency); Switched-mode power supply, https://en.wikipedia.org/wiki/Switched-mode_power_supply (a power transformer, filter capacitors, the circuit board; a USB charger as an example); USB hardware, https://en.wikipedia.org/wiki/USB_hardware (plugs and receptacles, USB cables, connectors); AC power plugs and sockets, https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets (prongs, blades, pins). (2) Ken Shirriff, Apple iPhone charger teardown, https://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html (the AC prongs, the case, two circuit boards, the two large electrolytic capacitors that smooth the power, the flyback transformer with its low-voltage output, the USB jack). Read for the names only; no maker's charger is drawn. (3) Makers' sheets for plug-in USB chargers on the Internet Archive, from four unrelated makers: https://archive.org/details/manualzilla-id-7092602 (USB charge ports), https://archive.org/details/manualzilla-id-7140436 (USB ports), https://archive.org/details/manualzilla-id-7161151 (USB cable, connector tips) and https://archive.org/details/manualzilla-id-7143220 (USB cable). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain shapes; own work, no maker's charger copied. Licence: own work

How it works

These are the parts of a charger of the plug-in kind that charges a phone. The first drawing shows the outside with its cable. The second shows the inside, so nobody has to open one.

Read the full guide

From the wall to the phone

The prongs go into the wall outlet. Inside the case, a circuit board holds the electronics. The capacitors smooth the power and the transformer passes it from the high-voltage side to the low-voltage side. The power leaves through the USB port. The USB cable has a connector at each end: one fits the port and the other fits the device.

  • The part in the wall is the charger. The cord is a USB cable, and it comes apart from the charger.

Questions and answers

What are the parts of a phone charger called?

On the outside: the prongs, the case and the USB port, plus a USB cable with a connector at each end. Inside the case: a circuit board that carries a transformer, capacitors and smaller electronic parts.

What is inside a charger?

A small circuit board. The largest parts on it are usually a transformer and one or two can-shaped capacitors. Together with smaller parts they turn mains power from the wall into low-voltage power for the USB port.

What are the metal parts on a charger called?

Prongs. They are also called blades or pins, depending on their shape. They go into the wall outlet.

Is the cable part of the charger?

On most phone chargers the cable is a separate part. It plugs into the USB port on the charger and into the charging port on the phone.

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