Wireless charging: two coils, no wire
How a changing magnetic field from the pad's coil induces current in the phone's coil (Qi), and why alignment matters.
No wire… so how does your phone charge? ⚡📱
1️⃣ THE PAD = A COIL: the charging pad sends AC through a flat copper coil. That makes a magnetic field that flips back and forth super fast — about 100,000–200,000 times a second (Qi).
2️⃣ THE PHONE = A 2ND COIL: a coil inside your phone catches that changing field, and a current flows in it. The phone turns that AC into DC for the battery. It's the same idea as a transformer — just with an air gap!
3️⃣ LINE THEM UP: if the coils are off-centre, less of the field reaches the phone, so it charges slower and gets warmer. Qi2 magnets (like MagSafe) snap the phone into the perfect spot.
💡 A cable still wastes less energy as heat than wireless.
Two coils, no wire.
Read the voiceover (transcript)
- No wire. So how does it charge?
- The pad's coil makes a magnetic field that flips back and forth, super fast!
- A coil in your phone catches that field, and a current flows. Just like a transformer!
- Misaligned coils charge slower and hotter. Qi2 magnets line them up!
- Two coils, no wire!
- Next: noise cancelling! Follow for Part five!
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