# Electric voltage and electric current! Simple calculation

What if you could calculate the electrical current or electrical voltage of a circuit by doing just one calculation! In this article the World of Electrical shows an incredible trick to calculate the current and electrical voltage of an electrical circuit, so come on guys!

It is important to note that we are going to show you the two ways of doing the calculation. This is important for you to understand why the trick will make the bill much simpler and faster.

Electric voltage, how to calculate?
In this first circuit, the calculation is to find the voltage of resistor 2. To find this voltage we will need the current value that we do not have yet. So, to reach this value we will use the Ohm’s law formula: Current is equal to voltage, due to the sum of resistances. The current is what we are looking for, the voltage is 24V, the resistance 1 – 6Ω and the resistance 2 – 2Ω.

An electrical circuit, voltage, and electric current
Example of electrical circuit with the calculation of the voltage in the resistor

Performing the calculation, the result shows that the current of our circuit is 3A. After obtaining the current value, just use the ohm law again to find the voltage of resistance 2. Then just use the formula: VR2 is equal to resistance 2, times the current, and the result of the calculation shows that the voltage of our resistor 2 is 6V.

Calculation of electrical voltage
Formula for calculating the resistor voltage of an electrical circuit

Using our mallet it is possible to find the VR2 by doing just one calculation as shown in the image below! For this we will use the following formula: VR2 is equal to resistance 2, due to the sum of resistances, times the total voltage. Performing the calculation we can see that the result shows that the voltage of our resistor 2 is 6V.

Electrical circuit, voltage and electric current
Quick mallet to calculate the resistor voltage of an electrical circuit

Electric current, how to calculate?
In this second circuit, the calculation is to find the current that passes through resistor 2. To find that current we will need the voltage value that we do not have yet. So let’s use Ohm’s law formula: Voltage equals current, times resistances in parallel. Note that the voltage is what we are looking for, the current is 9A, the resistance 1 – 8Ω and the resistance 2 – 4Ω.

Calculation of electric current
Example of an electrical circuit with a calculation of voltage and current in the resistor

First let’s calculate the resistances in parallel with the formula: Resistance 1 times Resistance 2, divided by the sum of the resistances. Performing the calculation, the result shows that the value of the resistances in parallel is approximately 2.66Ω. Taking this value and multiplying it by 9A, we have 24V, which is the circuit voltage. Now we can find the value that passes through resistor 2, just divide the voltage by the value of resistor 2, and the result shows that the current that passes through resistor 2 is 6A, as shown below.

Calculation of electric current
Formula to calculate the resistor current of an electrical circuit

With our mallet, there is no need to count resistors in parallel, so we can find the current passing through resistor 2 by doing just one calculation! For this we will use the following formula: Current I2 is equal to resistance 1, due to the sum of resistances, times the total current. Performing the calculation the result shows that the current I2 is 6A.

Calculation of electric current
Quick mallet to calculate the resistor current of an electrical circuit

Electrical calculation, what is the importance?
If you have looked carefully at the two ways of calculating, you certainly noticed that with the mallet it is much simpler and faster, isn’t it? Maybe you’re wondering, but what do I want to learn that for? Before answering this, see this image below that shows a resistor association in parallel!

How to calculate resistors in parallel?