Figure 1: Graph of voltage over
time in charging a capacitor.
In charging a capacitor, when the
switch is closed, the charge builds up on the plates – rapidly at first and
then exponentially more slowly as repulsion between like charges accumulate on
the plates of the capacitor due to the separation of charge, a voltage develops
across the capacitor due to the electric field of these charges. In this
situation, work has to be done by increasing electric field as more charge is
separated.
switch is closed, the charge builds up on the plates – rapidly at first and
then exponentially more slowly as repulsion between like charges accumulate on
the plates of the capacitor due to the separation of charge, a voltage develops
across the capacitor due to the electric field of these charges. In this
situation, work has to be done by increasing electric field as more charge is
separated.
The energy stored in the
capacitor which is measured in joules is equal to the amount of work required
to establish the voltage across the capacitor, and therefore the electric
field.
capacitor which is measured in joules is equal to the amount of work required
to establish the voltage across the capacitor, and therefore the electric
field.
Energy or work done = Charge X
Potential difference
Potential difference
W = QV
And Q = CV
