Capacitors Flashcards
What is a capacitor and how does it work?
2 parallel plates, if a p.d is applied, the plates become charged which produces an electric field
What is the insulating material between the plates called?
Dielectic
What is the units of capacitance?
Farads
Why is it important that the + end is connected to the positive terminal of the power supply?
So the maximum p.d is not exceeded
How does a capacitor produce a constant voltage?
The capacitor will charge up until the charge is equal to the p.d. At this point no more charge can be stored therefore p.d will be constant
What are the factors that affect the capacitance?
Area of plates, distance between the plates and the insulator between them
How does a capacitor charge/discharge?
Exponentially
What does the time constant tell us?
How long it takes for the capacitor to fall to 37% of its initial value
How do you add capacitors in parallel?
Ct = C1 + C2
How do you add capacitors in series?
1/Ct = 1/C1 + 1/C2
What is the equation that links the permivitty of free space, area and distance?
EoA/d
What is capacitance?
The ability of a capacitor to store charge on its plates
When capacitors are in parallel, what is equal?
P.d
When capacitors are in series, what is equal?
Charge
If the resistance is lower, the initial current would be greater. How would this affect the charge that passes through?
The charge would pass through more quickly
