Capacitance Flashcards
What do capacitors effectively consist of?
2 conducting plates (electrodes)
What are the two conducting plates seperated by?
An insulator known as a dieletric
Give 3 examples of dielectrics.
Air,
Oil,
Paper
What is the gradient of a potential difference against charge graph?
The reciprocal of capacitance.
1/C
define capacitance
charge stored per volt
what is capacitance measured in?
CV^-1
microfarads symbol and how many x10^ what?
µ and x10^-6
nanofarads symbol and how many x10^ what?
n and x10^-9
picofarads symbol and how many x10^ what?
p and x10^-12
E = 1/2QV can also be written as:
E = 1/2CV^2 and E = 1/2 x Q^2/C
how do you charge a capacitor?
by connecting it to a battery
how do you discharge a capacitor?
take the battery out and then reconnect the battery
what does the time taken to charge/discharge depends on what 2 factors?
capacitance and resistance
the charge on a capacitor decreases how?
exponentially
what is the time constant?
the time taken for charge on a discharging capacitor to fall 37% or time taken for a charging capacitor to rise 63%