Flashcards
Capacitors
Cards in this deck (10)
- 1What is a capacitor?A device which stores electrical charge
- 2What is capacitance?The amount of charge the capacitor can hold
- 3What is capacitance defined as?The amount of charges stored per volt
- 4What is capacitance measured in?Farads
- 5How does a capacitor charge?A p.d is supplied to the circuit
Electrons flow to the capacitor and build up on the negative plate
Electrons on the positive plate are repelled by the negative plate
They go back to the cell
The current decreases as the electrons have to overcome the repulsion from the plate and put in work
When the p.d of the capacitor is the same as the cell then it is fully charged - 6What does a charging curve for a capacitor look like?
- 7How can you investigate the charged stored on a capacitor?set up test circuit to measure p.d and current
Adjust the variable resistor to keep charging current constant
record p.d at regular intervals until fully charged-equals battery
plot a graph from the results
IxT graph (area underneath=Q)
QxV graph (gradient=capacitance) - 8How do capacitors store energy?When charge builds up on the plates
- 9How can you find the energy stored by a capacitor?From the area under a p.dxQ graph
- 10What is the potential difference across the capacitor proportional to?The charge stored on it
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- Physics Unit 4 Flashcards on Capacitors, created by sammy414 on 01/12/2013.
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- sammy414
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