Electric CircuitA simple electric circuit consists of a voltage source, some
type of load, and conductors to allow electrons to flow between
the voltage source and the load.
Ohm’s lawshows that current varies directly with voltage and
inversely with resistance.
Current (I) is measured in amperes (amps)
Voltage (E) is measured in volts
Resistance (R) is measured in ohmsLaw Triangle
There is an easy way to remember which formula to use. By
arranging current, voltage and resistance in a triangle, you can
quickly determine the correct formula.
To use the triangle, cover the value you want to calculate. The
remaining letters make up the formula.
Ohm’s Law ExampleAs the following simple example shows, if any two values are
known, you can determine the other value using Ohm’s law.
Using a similar circuit, but with a current of 200 mA and a
resistance of 10W. To solve for voltage, cover the E in the
triangle and use the resulting equation.
Remember to use the correct decimal equivalent when dealing
with numbers that are preceded with milli (m), micro (m), kilo (k)
or mega (M). In this example, current was converted to 0.2 A,
because 200 mA is 200 x 10-3 A, which is equal to 0.2 A.