Capacitors and their vibes

what are capacitors?

• they store electrical charge and energy

• they consist of two conductive plates

• there is a gap or dielectric insulator between them which prevents charge moving between them

how does charge build up?

• capacitor connected to dc power supply

• current flows briefly from one side of the capacitor around the wires all the way to the other side of the capacitor (past the positive terminal of the battery)

• electrons build up on one plate, giving it a negative charge

• as the other plate has lost electrons, it is positive

• charge keeps building up until p.d across plates= emf of cell

• equal magnitude of charge on each plate

what is capacitance?

• amount of charge per unit potential difference that a capacitor can store across it

• Capacitance (farads) is charge (coulombs) divided by p.d (volts)

p