Decoupling Capacitors
Small capacitors placed next to each IC's power pins supply fast current spikes and keep the supply clean.
Easy
When a digital chip switches, it draws short bursts of current. The PCB traces back to the power supply have inductance, so without local storage the supply voltage at the chip dips and rings.
Standard practice:
- a 100 nF ceramic capacitor at every power pin, as close as possible, with short connections to ground;
- a bulk capacitor (e.g. 10 µF) per board section or regulator.
Short, wide connections matter more than the exact value — a capacitor 3 cm away with thin traces is far less effective.
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