Capacitor Series Part 6: Decoupling caps — the tiny capacitor beside every chip
A small 100 nF (104) ceramic cap right at a chip's power pins supplies the quick bursts of current the chip needs and soaks up noise, so the supply stays steady.
See that tiny capacitor next to EVERY chip? Here's why it's there! ⚡
When a chip switches, it needs a quick burst of current — right now, on every clock tick.
But the power supply is far away, at the end of long wires and traces. It can't react that fast, so the voltage at the chip DIPS… and a big dip can make the chip glitch or reset. 💥
The fix: a small ceramic capacitor right at the power pin. It's a tiny local tank that fills each burst instantly, then refills between them. The voltage stays steady. ✅
Rule of thumb: 100 nF (0.1 µF, marked "104") at every power pin, as close as possible, with a short path to ground.
Read the voiceover (transcript)
- See this tiny capacitor next to every chip?
- When a chip switches, it needs a burst of current. Right now!
- But the power supply is far away. The voltage dips, and the chip can crash.
- A small capacitor right at the pin is a tiny local tank. It fills the gap instantly.
- A hundred nano at every power pin!
- Next: the supercapacitor! Follow for Part seven!
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