Chapter 5- Capacitance Flashcards
Capacitance equation
C= Q/V
Q= CV
What do capacitors do
They store charge
Unit of capacitors
Faraday
Tend to use faraday to the x10^-6
V small
On graph of V against Q what is the work done
Area under the straight line
W= Vaverage Q
= 1/2 Vmax Q
W= V🔺Q
Work equations with substitution
W= 1/2 VQ
= 1/2 CV^2
= 1/2 Q^2/C
Capacitor circuit symbol
-•| |•-
Capacitor uses
Under the keys of the computer or Mobile phone
Detects change in charge as capacitance changes slightly when moved closer together
What kind of growth/ change does capacitance follow
EXPONENTIAL
What is exponential decay
When something gets smaller by the same fraction or proportion in each EQUAL interval of time
How to make exponential graphs easier to work with
Take a log-Lin graph
If an exponential growth or decay then the graph is a straight line (just not through origin)
e is a number equal to
2.718
Exponential function is written
e^x
An exponential with time graph is written w equation….
Y= y0 e^-kt
k= 1/RC
The relationship for capacitance discharge states….
The less you have the more slowly you lose it
What is the time constant?
RC
The larger the time constant the longer the decay takes
