The German physicist George ohms was the one that discovered the relationship between voltage, current, and resistance on an electric circuit. That was a very long time ago. He deduced that when temperature is constant, the current flowing through a fixed linear resistance is directly proportional to the voltage applied to it and at the same time inversely proportional to the resistance. From this discovery, he pointed out the relationship between voltage, current, and resistance, which gives rise to the basis of the law called ohms law.
Back at school, I was a science student, and I remember how our physics teacher taught us ohms law.
At first, it looks difficult, but after we understood the formula, it became easier, though some students still find it difficult. I’m sure if there were scientific calculators that could calculate ohms law then (probably we didn’t know), we would have gotten one for ourselves to save the stress of calculating ohms law on paper while answering objective questions.
Now that a lot of softwares are available, solving any calculation related to ohms law, and beyond has become easy. While gallivanting on GitHub, I found an app, and to be honest, it’s the first app I came across that is used to solve any calculations related to ohms law. I’m talking about
Ohms law x. The app is simple, so I won’t say much in this blog. I will only talk about the functions and how it can be used to calculate voltage, power, resistance, and current. Please read on.
Ohms law x
Ohms law x is an open source app that is used to calculate any value with power and another value like resistance, current or voltage. It is also used to calculate power with just one value.
Before you can use the app, you must understand ohms law and all the formulas
All calculations on ohms law have their formulas. Without mastering and understanding them, you will not understand how to use the app. There’re different units used as well, which must be understood. I will explain the formulas extracted from ohms law, and show some examples to make it more understandable.
Ohms law V = IR. Where V is said to be the potential across a circuit element, I denotes the current through the circuit or cable, and R as its resistance. This formula only applies to ohmic resistors.
To find the Voltage, (V)
[V = I x R] V (volts) = I (amps) x R (Ω)
To find the Current, (I)
[I = V ÷ R] I (amps) = V (volts) ÷ R (Ω)
To find the Resistance, (R)
[R = V ÷ I] R (Ω) = V (volts) ÷ I (amps)
First, let me list out the formulas
- V = IR
- I = V/R
- R = V/I
I will talk about power as we proceed.
From the formulas, note the following parameters.
V is denoted as
voltage in volts (V)
current in amperes (A)
resistance, in ohms (Ω)
power in watt (W)
So from the first formula, we have, V = IR. It means to calculate the voltage (V), we must multiply the current (I) by the resistance (R). That’s why V = IR. Hope you are following. All these for those who don’t know about ohms law.
The second formula
If you are following, we have the second formula to be I =V/R. How did we arrive at that? Let me explain.
We were able to get the second formula from the first one (V = IR) using the change of subject formula.
Since we want to make the current (I) the boss (permit me to use that word), we have to divide both sides by the resistance (R).
V = IR. So, to get the second formula, V/R =I
R / R---------------- If R council R, we will be left with V/R =I, which is the same as
I = V/R ------- Second formula.
We are using the same method for the third formula as well. Though we can use the second formula to get the third, it is a wrong way as we will arrive at the first following that process, which will eventually lead to the third formula, so it’s wise we use the first formula all through to cut long calculations and confusion.
Now using the first formula to get the third.
From the first formula V = IR. To get the Resistance (R), we must divide both sides by the current (I).
Let’s see how it goes.
IR/ I----------------- If I council I, we will be left with V/I =R, which is the same as
R = V/I. -------- Third formula
Let’s look at Electric power P = I × V
P = I V -----------4
P = I2 R -----------5
P = V2/R ----------6
Please note that I2 and V2 are in square. i.e, I square, and V square.
The fifth and sixth formulas above are derived from the fourth and first ohms law formula V = IR. I will show you how they arrived at it.
Just keep this formula in mind as we proceed
V = IR
Now, To get P = I2 R, we will substitute the value of pronumerals into P = I V . Substituting the value of pronumerals means to replace the pronumerals with their corresponding values. A pronumeral is a letter that is used to represent a number (or numeral) in a problem.
So, this is what we have
Since we already know that V = IR, then we have
P = I × I R. V is replaced with I R.
So, P = I2 R ----------5
For the last one. We have
P = V/R × V I is replaced with V/R from the formula I = V/R.
So, P = V2/R---------6
Those are the steps involved to arrive at the formulas.
Using ohms law x
The app has a simple interface where you can calculate the voltage, current and the resistance of a circuit, or a cable. To calculate the voltage, you will first need to switch to voltage V in the app. This will display spaces where you can input values of current and resistance. The same applies to others. So if you are calculating current, you will switch to Amperes (A), and for resistance, you switch to Ohms (Ω).
Power is calculated separately. If you look at the top right side of the app, you will notice a power button that can be switched on and off. To calculate power, the button must be switched on, which also displays another button that can be switched to either current or voltage.
Let’s do some calculations
W e already have the value for current and resistance, just including it in the calculation to explain the apps usage.
V = IR
From the above circuit, I =4A, and R =16Ω
V = 4 x 16 = 64V
I = V / R.
I = 64 / 16 = 4A
R = V / I
R = 64 / 4 = 16Ω
P = IV
P = 4 x 64 = 256W [App can't solve this type of calculation. It only calculate power with just one value.] Will talk about that with the PO in an issue on github.
All you need to do is input the values in the spaces in the app, and you will get the same answer as the ones above. Understanding the formulas and how to use them makes the app usage easy.
All ohms law formulas are in the app
Yes, the formulas are there to guide users on the right one to use in case of necessity.
Comparing with ohms law calculator
I used the ohms law calculator as well and discovered there are some differences between them. Fine, they both have a simple interface with attractive colours but using ohms law calculator seems a little difficult. For someone trying to understand the ohms law, I wouldn’t recommend it, though I love the display of the answers in red colour. It has the ohms law triangle, which I didn’t find on ohms law x, but the formulas in it are the same as they both explain the ohms law. These apps are simple, but they are doing a mighty work.
I’ve been able to explain the ohms law x, and the formulas associated with ohms law. You can download the app on Google play store and start using it for any related ohms law calculations. Ohms law is a bit wider than what I’ve explained, so if you have any question or additional explanations, please feel free to comment below this post. I would be glad to have a chit chat regarding this. Thank you for reading to the end.
This is ckole (the laughing)