Everyday Tech Part 7 — how tap-to-pay works (NFC)
The reader's coil makes a fast-flipping magnetic field (NFC, 13.56 MHz); the card's hidden coil turns it into power for its chip (no battery), it only works within about 4 cm, and every tap sends a new one-time code.
Tap, beep, paid! But how does tap-to-pay actually work? 💳📶
📡 The reader sends out a magnetic field that flips 13.56 million times a second (NFC).
🌀 Your card hides a coil (an antenna) and a chip — but no battery!
⚡ Near the reader, the field makes a current in the coil and powers the chip — like wireless charging.
🤔 So why must you get so close?
📏 The field fades FAST: it only works within about 4 cm (1.5 in).
🔐 And every tap sends a new one-time code, so a copied tap won't work again.
Read the voiceover (transcript)
- Tap, beep, paid! But how?
- The reader sends out a magnetic field.
- Your card hides a coil and a chip!
- The field powers the chip, no battery needed!
- So why so close?
- It fades fast: about four centimetres!
- Each tap sends a one-time code.
- Next: how your phone feels tilt. Follow for Part eight!
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