Ohm's law states that current is directly
proportional to voltage and inversely proportional to
resistance, so the higher the voltage the higher the current -
as long as the resistance remains constant. Except as we
always see, the current is also determined by the resistance
(resistance is the opposition to current flow). as long
as voltage is constant, the higher the resistance - the lower
the current and visa-versa.
|Current = I
Voltage = E
Resistance = R
law can be shown by three different formulas
To find Current I =
To find Voltage E =
I x R
To find Resistance R = E/I
Use the circle by covering the unknown value
with a finger.
(Example if the unknown value is Voltage - cover the
equation remaining is I x R).
|Besides the three basic electrical units (current,
voltage and resistance), there is a forth unit -
Power. The measurement of power is "Watts".
Power is the quantity of work done in a determined
amount of time.
One Watt is equal to the
work done by one volt moving a current of one ampere.
Power is directly proportional to both
current and voltage.
So the equation is :
P = I x E
|The Circle shows three formulas for each quantity
using the power formula and Ohm's Law.
Using the circle you can find a correct formula
for any problem if two quantities are known.