WARNING: This product contains nicotine.
Nicotine is an addictive chemical.

VU301 Intro to RDAs and Ohm's Law

Welcome to another exciting lesson from Vape Education, at Mister-E-Liquid.com. In this lesson, we're going to talk about the advantages of Rebuildable Atomizers, for those interested in building their own atomizers, rather than using tanks. We'll discuss the basic characteristics of RDAs, but first we need to cover some important basic characteristics of electrical circuits.

Any electrical circuit can be characterized by a few basic measurements, which act against each other to produce the total values for that circuit. Voltage (measured in Volts) is a measure of the potential difference in a circuit, and it's what's doing work to heat up your coils and produce vapor. Resistance (measured in Ohms) is a measure of how easily the voltage is able to move through the circuit; the more easily the voltage can move, the more work it can do. Amperage (measured in Amps) is the amount of current moving through the entire circuit.

Geekvape GBOX Squonk 200W Box Mod with Geekvape Peerless RDA, with build tools

Geekvape GBOX Squonk 200W Box Mod with Geekvape Peerless RDA, with build tools

It's important to understand these factors so you can understand how the electrical circuit of your RDA will behave for a given voltage input, and make sure the circuit you have constructed is not above the amp limit of your battery. Running a battery above its amp limit is highly dangerous, and can cause the battery to overheat and vent - and in this context, "vent" can mean "explode". So make certain you understand fully how these factors interact with each other before ever firing up that RDA!

Diagram showing the path of electricity through a regulated mod, and adorable characters acting out the relationship of Amps, Volts, and Resistance

Diagram showing the path of electricity through a regulated mod, and adorable characters acting out the relationship of Amps, Volts, and Resistance

Fortunately, today's regulated mods do all this math for you, preventing you from asking more from your battery than it can handle, but mechanical bods and unregulated box mods require extreme caution. And even for regulated mods, you'll still need to know what resistance to build at to get the results you're seeking, so you've still gotta understand the math, I'm afraid.

There's a series of equations that can be used to solve for whatever factor you need to calculate. Ohm's Law tells us that the amperage is proportionate to the voltage, divided by the resistance, giving us the equation:

Diagram showing the relation of Amps, Volts, and Resistance

Diagram showing the relation of Amps, Volts, and Resistance


Simple algebra allows us to solve for other missing factors thusly:


Calculating wattage, a function of volts and amps, is just as simple:


So let's dip back into application before your eyes totally glaze over.

Let's say you have a 4 volt battery feeding a circuit with 1 ohm resistance. We know the voltage and resistance, so we need to solve for amperage. Looking above, we see that Amperage is Voltage divided by Resistance, so A=4/1, or A=4. The battery in this circuit would need to have a relatively mild 4 amp limit.

In a more extreme example, let's say you've built a low-resistance 0.2 ohm coil. This low resistance means far more current is free to flow through the system for the same amount of voltage. The Amperage is, again, Voltage divided by Resistance, so A=4/0.2, or 20 amps. For a battery with that kind of amp limit, you need a high-drain IMR battery whose chemistry is selected to provide stable voltage at high current loads. Running this circuit with low-amperage batteries would result in damage to the battery, and possibly to the mod and to the user!

So, moving on from electricity, let's talk about RDAs. An RDA is a Rebuildable Dripping Atomizer, and at its simplest, it's a coil of resistance wire, wrapped in e-liquid-soaked wick, which heats up when electricity is applied to it, producing vapor. RDAs come in single- and multiple-coil designs, with most offering the option of single-coil or dual-coil. Remember when solving for the amp limit of your circuit that BOTH coils must be taken into consideration! Two 0.1 ohm coils produce a resistance of 0.05 ohms, requiring 80 amps at 4 volts!

Geekvape GBOX Squonk 200W Box Mod with Geekvape Peerless RDA

Geekvape GBOX Squonk 200W Box Mod with Geekvape Peerless RDA

The general tendency for RDAs is that single-coil setups produce better flavor, while multi-coil builds produce more vapor, but it's not a zero-sum game: some multiple coil builds will produce excellent flavor, and some single-coil setups are quite capable of producing more than enough vapor for anyone. The airflow, wattage, wicking, and other characteristics of the RDA will determine the final vaping characteristics of the RDA. Experimentation is key to discovering the ideal setup for you!

For more specific details on how to build RDAs, including specific instructions for wrapping and wicking, please continue with our upcoming lessons in this series, which will give a detailed breakdown of methods, best practices, and pro tips.

That's all for today's lesson on the basics of RDAs and Ohm's Law. If you have any additional questions, please don't hesitate to contact us, either by phone at 855-647-8373, by email at CustomerService@Mister-E-Liquid.com, or via live chat on any page of Mister-E-Liquid.com. If social media's more your thing, you can find us on Facebook or Instagram: we're always happy to help!

Thank you for joining us today at Vape Education. Class dismissed!

  • Related Products
Now Available! Vaporesso XROS Pod Systems are here.
The Vaporesso XROS Pod System crosses the limits of what an ordinary pod system can do! With refillable magnetic 2 ml pods, optional draw activation, USB-C fast-charge, and one of the smallest bar vape designs you've ever held, the Vaporesso XROS is perfect if you want to get small, but vape big!
Shop Now
It is illegal in the United States to sell tobacco and nicotine products to minors. By viewing and visiting Mister-E-Liquid.com you are confirming that you of legal smoking age for the state in which you reside. Thank you for your cooperation.
*Free shipping not applicable if adult signature is required for delivery.

Customers In States With Active Flavor Bans:
All our Mister-E-Liquid Clear and our Signature Tobacco Series products are available on our Flavor Ban compliant site, Mister-Es.com!

For all US states, the legal age to purchase is now 21 years old.