The capacitance depends on K, A, k and d:
Cparallel plate = K A / (4 p k d)
where K = 1 for vacuum, A = 5 cm x 5 cm = 25 cm2 = 25 x 10-4 m2, d = 2
mm = 2 x 10-3 m, and k = 9 x 109 Nt-m2/Coul2 , so C =
Besides this basic equation for power:
P = I*V
remember we also have Ohms Law:
V = I*R .
Thus we can write the following equations for power:
P = I2*R = V2/R
= I*V .
To see which one gives the most in
We define capacitance as the amount of charge stored per volt: C = Qstored
/ DV.
UNITS:
Farad = Coulomb / Volt
Just as the capacity of a water tower depends on the size and shape, so
the capacitance o
Now that we have the concept of voltage, we can use this concept to
understand electric circuits.
Just like we can use pipes to carry water, we can use wires to carry
electricity. The flow of water th
If a capacitor stores charge and carries voltage, it also stores the energy it
took to separate the charge. The formula for this is:
Estored = (1/2)QV = (1/2)CV2 ,
where in the second equation we have
For a parallel plate capacitor, we can pull charge from one plate (leaving a
-Q on that plate) and deposit it on the other plate (leaving a +Q on that
plate). Because of the charge separation, we have
Using C = Q/V, we see that in series the charge moved from capacitor 2s
negative plate must be moved through the battery to capacitor 1s positive
plate.
But the positive charge on the left plate of C
In this first part of the course we will consider two of the common circuit
elements:
resistor
capacitor
The resistor is an element that resists the flow of electricity.
The capacitor is an element th
V=I*R, or R = rL/A
For parallel, both resistors are across the same voltage, so Vtotal = V1 = V2 .
The current can go through either resistor, so:
Itotal = (I1 + I2 ) .
Since the Is are in the denomin
Instead of making and storing all sizes of resistors, we can make and store
just certain values of resistors. When we need a non-standard size
resistor, we can make it by hooking two or more standard