No doubt by now you've learned more about electricity from vaping than you ever did in high school!
Especially if you bought a mechanical mod, you would have very quickly learned about voltage, amperes, resistance in ohms, and how important it is to your personal safety to get it right. But even if you always used regulated mods or fixed voltage/wattage devices, you would have picked up on resistance in ohms - the lower the resistance, the hotter the vape and therefore the more the vapour, and you probably figured out the weird thing that the lower the resistance, the higher the power needs to be.
But honestly - how does this stuff actually work? Exactly what have I got myself into here? Also, I really want a mech mod, but I've got no idea how to build it right, so where do I even start?
Even though both my dad and stepdad were electrical engineers, I was still somewhat ignorant of the whole caper until vaping introduced me to these finer aspects. Now it has finally twigged (somewhat), I would like to explain how it works in layman's terms, to give you a leg-up in your own understanding. So let's get into it!
Starting with the easiest, everyone knows what electricity is, right?
Actually, everyone probably knows what it looks like, what it does, and how to use it, but maybe isn't so up on what it actually is, so let's start with this.
What we call "electricity" is the flow of electrons from one place to another. Electrons are negatively charged particles that orbit the nuclei of atoms (nerd alert).
When you fire your mod, it completes a circuit that allows electrons to flow from the battery to your coil.
Amps are a unit of measurement to describe the flow rate of electrons through any given point at one time. Increase the current flowing through the circuit and the amps increase, and vice versa.
This is not to be confused with milliAmpere hours (mAh), which is a unit of electric charge. One ampere hour is the equivalent of the charge transferred at a constant one ampere for one hour. Therefore, a 4400mAh battery has enough charge to run at one amp for 4.4 hours.
Voltage is a concept that is actually poorly understood. We know the good old 9V battery, and we know about adjusting the voltage of our mods, but what is a volt?
A volt is a measure of potential energy between two points. In other words, it is a measure of how much electricity could be transferred between two different points when a current is applied.
For example, when using a mechanical mod, a freshly charged battery is capable of delivering 4.2 volts, meaning that when you complete the circuit between the positive and negative terminals, there is 4.2 volts worth of potential energy. As the battery's charge is used up, the voltage drops, because the potential energy released decreases due to the decrease in stored electricity.
In a regulated mod, the circuitry has the ability to drag electricity out of the battery at a constant rate - it acts as a throttle. So if you set your mod to pump 3.9V into your coil, it is draining less than the potential energy of the battery to begin with, and more than the potential as the charge decreases.
Watts are a measure of power. The watt is a unit to describe the rate at which energy (measurable work ability) is produced. Therefore setting your variable wattage mod to a specific wattage is setting it to produce a certain amount of energy at a certain rate.
In regulated mods, watts and volts are related in terms of the end result, but are two separate means. When adjusting wattage, a regulated mod will adjust the voltage to the level required to produce the desired amount of energy. Adjusting the voltage directly will necessarily change the wattage; the higher the voltage, the higher the energy output, which is measured in watts.
The ohm is a unit of electrical resistance. In other words, it measures how much a conductive medium resists the flow of electrons. The higher the resistance of a conductive medium (such as the coil in your atomizer) the more it will resist the flow of electrons through it.
The resistance of a conductive medium (or impedance) can be determined by the formula Ω=V/A. Therefore, if applying 1.0V through a wire results in 1.0A of electricity, the resistance of the wire is 1.0Ω. You can also flip this around to determine how many amps are flowing by the formula A=V/Ω. Therefore, 4.2V flowing through a 1.2Ω coil is drawing 3.5A of current.
In an atomizer coil, electricity that is not allowed through is converted into heat. Therefore, the higher the resistance, the less electricity is needed to heat up the coil. The lower the resistance, the more power is needed.
The Ohm's Law Triangle was hinted at above - resistance, amperage and voltage can all be derived from each other:
In a simple electrical circuit such as an atomizer coil, the impedance is directly affected by the volume of the resistive material. In other words, the more metal there is, the less resistance there is. This is why putting two 1.0Ω coils into an atomizer will result in an overall resistance of 0.5Ω, and why 24 gauge wire has less resistance than 28 gauge wire.
Putting it all together
The higher the resistance (Ω), the less power (W) is needed to produce heat from the same amount of current (A) drawn from the potential (V) of the battery.
However, increasing the resistance does not mean bigger clouds! This is due to the proportional relationship between the amount of energy flowing through the conductor and the amount of heat able to be generated - if hardly any energy is flowing through the wire, hardly any heat can be produced; however if lots of energy is flowing through the wire, the volume of energy converted to heat will be higher. Which means in order to produce more heat (and bigger clouds) you have to lower the resistance and increase the power exponentially.
This is why sub-ohming was born. By lowering the resistance of the wire, you are increasing its capacity to transfer energy, and increasing the energy that is then transferred into heat.
This is also why you need more power (W) to fire a coil at lower resistances (Ω). Putting a small current through a low resistance wire will mean the majority of the energy is dissipated into the negative pole of the atomizer, meaning no heat. In order to fire sub-ohm coils, you need lots of energy to get heat from the available voltage, but the heat you get is directly proportional to the amount of energy flowing through.
Regulated mods take the hard work out of the equation, but you still need knowledge of the above concepts to ensure you are using your mod battery efficiently. Not getting the resistance right can have dire consequences for your equipment - too much power through too much resistance will cause the current to bounce back along whatever path it can find, meaning not just through the negative pole of your atomizer, but possibly into the circuitry, back into the battery, or worst-case scenario into the body of the mod and/or your hand!
I highly recommend using the Watts/Volts/Amps/Ohms online calculator if you're building for a mechanical mod, or if you're just curious about why your battery always seems to be running flat.
So stay safe out there and have fun playing with power!