In the Watts Amps Ohms and Volts video I explained how current and resistance is like water flowing through a hose. Now I’ll use those concepts to show how dual parallel coils work. Imagine these are wires on two different atomizers.
Out of the two the thinner wire has a higher resistance because the current flow is more restricted. But if we add a second wire like this, the current has two wires to flow through. So the resistance drops.
If the length and thickness of the wires are about the same the resistance is cut in half. Here’s how it looks on a dripper. If we have a single one ohm coil, the resistance is just simply 1 ohm. If we add another one on coil in parallel, the current will flow through two wires.
So the total resistance is reduced to .5 ohms. To get 1 ohm using two coils each coils will have to be 2 ohms. So we end up using four times more wire than a 1 ohm single coil build using the same wire.
Coils are consider to be in parallel because of how they’re wired not just because they look parallel. Each coil has to have one and connected to the positive post with the other end connected to ground, but as you can see this atomizer had two ground post.
So I can place the coils like this and I’ll still be considered parallel, it’s wired like the diagram. And these ones as well. But a build like this is not. There are two coils, but it’s made using one wire.
For dual coil to work properly the resistance of each coil has to be roughly the same. Otherwise, the current does not split evenly so the coils don’t fire evenly. This is the equation to calculate parallel coils.
You basically divide the resistance by the number of coils. We already know that with two coils the resistance is half. But if there are four coils, it drops the resistance even lower. Remember this is only if each coil has roughly the same resistance or else the question is not so simple, which will never use anyways.