CAPACITOR BASICS

Two plates and a gap

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A capacitor is two conductive plates separated by an insulating dielectric. Apply a voltage, and positive charge builds up on one plate while equal negative charge builds up on the other. The dielectric blocks current flow but lets an electric field build between the plates — that's where the energy lives.

No chemical reaction happens here — just charge physically separating. That's why capacitors can charge and discharge so fast.

WHY SO FAST

Speed vs. capacity

Because energy storage is purely electrostatic (charge separation, not a chemical reaction), capacitors can deliver very high power — often exceeding several kW/kg — and survive millions of cycles. The tradeoff: electrode surface area is small, so there's only so much charge to separate in the first place.

A capacitor's power is limited mostly by internal resistance, not by chemistry — which is exactly why it can't store much energy either.

UNIT 2 STUDY COMPLETE

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Ready for the Fab Challenge?

You've covered dielectrics, plates, and why ordinary capacitors trade energy density for speed.