February 7, 2017

Ohm’s Law


When you first start vaping, you shouldn’t worry about trying to wrap your head around Ohm’s Law. It is irrelevant and will only confuse you.

The manufacturer of your starter device surely knows all about Ohm’s Law and designed your device around it. Most beginner vape setups do not have fixed variables so you have nothing to worry about.


Georg OhmIf you’re ready to venture off into the vast world of rebuildable atomizers and mechanical mods, then Mr. Ohm needs to become one of your best friends. The reason you need to become well acquainted with Ohm’s law is because you’ll be using atomizers that don’t have a set resistance and batteries that don’t have a middle man regulating their current.

Regulated mods have safety features that are pretty good at preventing you from screwing things up, even when you build your own coils. When using mechanical mods, your brain has to act as the safety mechanism. Part of keeping safe is knowing Ohm’s Law.

What Exactly Is This Ohm’s Law Thing?

Ohm’s Law is a simple little formula that allows you to accurately calculate the way electrical current flows through a circuit. The formula is as follows, I=V/R. Don’t worry about what the variables stand for just yet. We’ll be covering that in detail in the following sections.

Knowing Ohm’s Law is really important when it comes to battery safety. If you create a build that happens to make you exceed the amperage limit of your battery, you’re in danger. You could damage your battery or even cause it to catch fire or explode.

This is why it’s important to use an Ohm reader when building coils. Another smart thing to do is to use an online Ohm’s Law calculator to make sure you’re not exceeding your battery’s amperage.

V =Voltage (V=I*R)

ohms-law-triangleIn the Ohm’s Law equation, the variable V stands for voltage. Voltage is sort of like the pressure. Picture a wire that has electrical current running through it. Now picture the current being forcefully pushed through the wire. The pressure that is pushing the current through the wire is called the voltage.

The voltage is coming from the power source and pushing electricity though the wires. For vapers, you can find the voltage by looking at the specs of a battery. Batteries come in all different voltages. Even some of the lower end ego batteries have a variable voltage setting.

It’s pretty intuitive, but it’s worth mentioning that voltage is measured in volts. You’ll see why I mentioned it when you get to the next section.

I = Current (I=V/R)

The variable I stands for current. Seems a little odd until you know the history behind the variable. Let me explain it as briefly as possible. The variable I stems from the French, “intensité de courant,” which means “current intensity.”

The current is the amount of electricity or electrons that are flowing through a circuit. Remember, voltage is the pressure that is pushing the electricity though a circuit while current is the actual amount of electricity that is passing through a given point in a circuit. They sound similar but they are distinctly different.

The measurement for current is a little less intuitive than the measurement for voltage. Current is measured in Amps.

R = Resistance (R=V/I)

The R in our Ohm’s Law equation stands for resistance. Resistance means exactly what it sounds like. It’s a measure of how hard it is to push an electrical current through a wire.

If you have two wires that are the same length, the one with the smaller diameter will have a higher resistance. The thinner the wire, the harder it is to push the current through. Another way to say it would be, the thinner the wire the higher the resistance.

Gauge is the unit of measurement for the diameter of a wire. The lower the Gauge, the bigger the diameter of a wire. The higher the Gauge, the smaller the diameter. High Gauge wires have a higher resistance since there is less room for electrons to pass through.

Resistance is measured in Ohms and the symbol for it is Omega (Ω). On some websites you see the resistance of an atomizer stated like this, 0.3ohm while on other sites you’ll see it listed as 0.3Ω.

Calculating Wattage

If you know the voltage and the resistance you can calculate the wattage or power by using the equation P=V²/R.