Store energy in an electric field; I=C dV/dt.
A capacitor stores charge Q=CV and energy ½CV². Current i=C dv/dt, so it blocks DC and passes AC. Capacitance C=εA/d. Types: ceramic, electrolytic, film. Used for filtering, timing and energy storage.
A 1000 µF capacitor at 12 V stores 72 mJ.
Capacitors store energy in an electric field, so they smooth power supplies, store charge for timing and block direct current.
Store energy in an electric field; I=C dV/dt.
Capacitors store energy in an electric field, so they smooth power supplies, store charge for timing and block direct current.
Once charged, it draws no steady current, so in the steady state it looks like an open circuit to DC.
Choose a rating above the maximum voltage it sees with margin, because exceeding it can break down the dielectric.
Typical applications include adding decoupling capacitors next to a microcontroller pin, designing a flash camera that stores energy quickly and smoothing the output of a rectifier in a power supply.
Study "Conductors, insulators and semiconductors" first (topic 15 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
Unit: farad. Voltage cannot change instantly. Electrolytics are polarised.
A 1000 µF capacitor at 12 V stores 72 mJ.
The next topic is "Inductors", which builds directly on this one.
It is classed as Beginner in Electrical Engineering (topic 16 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.