Capacitance 4.1 Flashcards
Define a capacitor?
consists of 2 conductors (plates) separated by an insulator (dielectric)
formula for charge
Charge = Capacitance X voltage
define capacitance?
the charge needed to raise pd by 1 v (c)
formula for energy of capacitance?
e = 1/2 capacitance X voltage ^2
in capacitors in parallel total charge is…
Qt = Q1 + Q2 + Q3 +….
in capacitors in parallel total capacitance is…
Ct = C1 + C2 + C3 +…
in capacitors in series total charge is…
Qt = Q1 = Q2 = Q3 = ….
in capacitors in series total capacitance is…
1/Ct = 1/C1 + 1/C2 + 1/C3 +…
Capacitor charges quickly when…
Little resistance in the circuit
Capacitor charges slowly when…
Lots of resistance in the circuit
Exponential decay equation?
Charge = Initial Charge X e ^-1/Resistance X capacitance X time
(same goes for current and voltage)
Time constant ?
time taken for charge to drop by a factor of 1/e
equation for time constant?
Time constant = resistance X capacitance
link between area and capacitance
Capacity is directly proportional to area of the plates.
link between distance between plates and capacitance
Capacitance is inversely proportional to the distance between plates.
conducting plates formula?
capacitance = @ X Area / Dst between plates
@? (epsilon)
8.85 X 10^-12
whats the constant epsilon mean?
Permittivity of the dielectric
define electric field
region where an object experiences a force define uniform eletric field
define uniform electric field?
region where the field strength is same in magnitude in all directions
define the electrical potential energy?
work it can do due to its position in the field.
define the potential difference?
work done per unit charge
equation for speed of particle between plates?
v = root(2 charge voltage / mass)
KE gained by particle =…
EPE lost by the particle
