Inside How Apple devices work, one part at a time

iPhone

MagSafe

A wireless charger works best when its coil sits right under the phone's coil. MagSafe puts a ring of magnets around both, so the charger finds that spot on its own.

Charger puck, cut away to show its coil and magnetsPhone back, windowed over its own coil and magnet ringGantry ruler: 2 mm ticks, 10 mm majorsCharging passes energy between the two flat coils, and the further the charger's coil sits off the phone's, the less of its field the phone's coil catches. Both coils are ringed with arc magnets, and the pull between the rings slides the free-running carriage back until the coils line up. Arrow keys nudge the puck; Shift nudges further.

Two coils, one gap

Wireless charging passes energy between two flat coils through a changing magnetic field. The further one coil slides off the other, the less of that field the phone's coil catches, and the more of the energy turns into heat.

Magnets that line things up

MagSafe arrived with iPhone 12 in 2020. A ring of magnets around the phone's coil meets a matching ring around the charger's coil, and the pull between them centres the charger without anyone looking.

The same ring holds cases, wallets and stands. Qi2, the newer open wireless charging standard, is based on MagSafe's magnetic alignment.

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