With our Ohm's Law Calculator you can calculate any of the unknowns involved in it as long as you know the value of the other two unknowns. Know the value of the resistance, voltage or current of the circuit you want:
Definition Ohm's Law
The Ohm's Law is one of the pillars of the world of electricity and electronics and thanks to it we know that:
The intensity of the electric current (I) flowing through an electrical conductor is directly proportional to the applied potential difference (V) and inversely proportional to its resistance (R).
This potential difference mentioned in the definition of Ohm's Law is the main reason that causes the movement of electric charges through a conductor.
Ohm's Law Formulas
To understand a little more how Ohm's Law worksIn this section, we are going to see which are the different formulas that we can use depending on the variable we want to calculate:
Voltage = Current x Resistance
Current = Voltage / Resistance
Resistance = Voltage / Current
These are the three formulas of Ohm's Law. If you don't remember any of them, there is a trick that consists of drawing a triangle like the one above these lines. Now place the letters VIR as they appear in the picture and draw a line just above the letters IR.
To remove the formulas of Ohm's Law with this mnemonic rule just cover with your finger the letter of the variable you want to calculate and the formula will automatically appear in the triangle. Do the test and cover the I, you will see that you get V/R. Like this with the rest of the variables.
Another important aspect of the formulas are the measurement units. Remember that voltage is measured in Volts (V), current in Amperes (A) and resistance in Ohms (Ω).
Ohm's Law Exercises
We are going to invent a Ohm's Law practical exercise in which we will calculate the current that passes through a wire if we have a 220V source and a resistance of 1200 Ω.
We resort to the formula given by the intensity value and we have that:
I = V/R = 220V / 1200Ω = 0.183A.
We are asked to calculate the resistance in a circuit fed by a 50V source through which a current of 2 Amperes flows.
R= V/I = 50V / 2A = 25Ω
To cover the other variable of Ohm's Law exercises, we now go to calculate the voltage of a circuit which has a resistance of 20Ω and through which a current of 3A flows:
V = I x R = 3A x 20Ω = 60 Volts
If you have any questions about Ohm's Law leave us a comment and we will help you.