Ohm's Law Calculator | Defined, Explained, Formulas, Triangle, Wheel
Understanding electricity, which is fundamental to our daily lives, requires a basic knowledge of certain key principles.
Among these is Ohm's Law, a concept that articulates the relationship between voltage, current, and resistance in electrical circuits.
Published: 31.07.2023.
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What is Ohm's Law?
Ohm's Law is a cornerstone in the field of electrical engineering, fostering a coherent comprehension of how electrical devices function and how they can be designed and manipulated for various purposes.
Named after the German physicist Georg Simon Ohm, this law is an essential principle that underpins a multitude of technologies that we encounter every day.
Whether it's the smartphone in your pocket, the refrigerator in your kitchen, or the computer on your desk, each is a testament to the practical application of Ohm's Law.
By comprehending this concept, we not only understand how these devices work, but we also learn how to troubleshoot them when they fail.
Ohm's Law is an empirical formula that describes the correlation between the three fundamental quantities in electrical circuits, namely, voltage (U(V)), current (I(A)), and resistance (R(Ω)).
This relationship is mathematically represented as:
I(A) = U(V) / R(Ω)
meaning that the current is equal to the voltage divided by the resistance.
In more practical terms, this formula indicates that the electrical current flowing through a conductor (such as a wire) is directly proportional to the voltage applied across it and inversely proportional to its resistance.
Simply put, a higher voltage leads to a higher current, and a higher resistance leads to a lower current.
Using this basic formula, we can also write:
U(V) = I(A) * R(Ω)
R(Ω) = U(V) / I(A)
These crucial equations allow engineers to design electronic devices with the desired properties by adjusting the circuit's voltage supply or resistance.
Ohm's Law Triangle/Pyramid
When trying to remember Ohm's law, perhaps the best way is to use the so-called Ohm's Law Triangle (also known as Ohm's Law Pyramid), which visually describes the relations between voltage, current, and resistance:
Ohm's Law triangle → voltage U(V) is "above" current I(A) and resistance R(Ω), helping us to write these three basic Ohm's Law formulas easily:
I(A) = U(V) / R(Ω)
U(V) = I(A) * R(Ω)
R(Ω) = U(V) / I(A)
Ohm's Law Wheel
Similarly to Ohm's Law Triangle, which contains basic Ohm's Law formulas, Ohm's Law Wheel expands these formulas using one more electric circuit value - power given in Watts P(W).
Ohm's Law Wheel lets us quickly find the relation between current, voltage, resistance, and power.
For example, if You want to find formulas for resistance R(Ω), check the lower right quadrant:
R(Ω) = U/I = U^{2}/P = P/I^{2}
Similarly, one can write down current, voltage, and power formulas.
Ohm's Law Calculator
To find out voltage, current, and resistance according to Ohm's Law, feel free to use the following Ohm's Law calculator - write your values and click Calculate:
Resistance (Ω)R(Ω) = U(V) / I(A) |
Current (A)I(A) = U(V) / R(Ω) |
Voltage (V)U(V) = I(A) * R(Ω) |
Current (A): Voltage (V): Resistance (Ω): |
Resistance (Ω): Voltage (V): Current (A): |
Resistance (Ω): Current (A): Voltage (V): |
Ohm's Law Frequently Asked Questions (FAQ):
Here are some of the most common Ohm's Law Frequently Asked Questions (FAQ):
What are the 3 formulas in Ohm's Law?
Three formulas of Ohm's Law include:
I(A) = U(V) / R(Ω)
U(V) = I(A) * R(Ω)
R(Ω) = U(V) / I(A)
The easiest way to remember them is using Ohm's Law triangle or pyramid, where Voltage (V) is "above" Current (A) and Resistance (Ω), helping one write these formulas.
What is R in Ohm's Law?
R in Ohm's Law is the resistance of the electric circuit and is given in Ohms (Ω).
What is I in Ohm's Law?
I in Ohm's Law is the current of the electric circuit and is given in Amps (A).
What is V in Ohm's Law?
V in Ohm's Law is the voltage of the electric circuit and is given in Volts (V).
Note: to emphasize that the Voltage is "potential difference," we are using capital "U" instead of capital "V" for voltage, which is also correct. And it greatly helps avoid confusion in many situations.
What is E in Ohm's Law?
Some authors use E instead of V or U for voltage or potential difference in the electric circuits. Personally, it may lead to confusion with Energy [E(J)] and Power [P(W)]. But, technically speaking, a potential difference is actually an "electric potential difference," so they are not wrong.
How to use Ohm's Law wheel?
Ohm's Law wheel simplifies finding the correct formula of the Current (I(A)), Voltage (U(V)), Resistance (R(Ω)), and Power (P(W)).
For example, if we want to calculate resistance in the electric circuit, we check the lower right quadrant and write down:
R(Ω) = U/I = U^{2}/P = P/I^{2}
Now, we can use one of these formulas (depending on the available units/values) to calculate resistance (Ω) in the electric circuit.