Two coils in serial, connected in parallel to a second pair of serially connected coils. Or the other way around: Two coils in parallel, connected in serial to a second pair of parallelly connected coils. Total resistance is the same as for a single coil. (1 R)

Two coils in parallel. Total resistance is halved. ( 1 ⁄ 2 R) Two coils in serial. Total resistance is doubled. (2 R) All three coils in parallel. Total resistance is divided by three. ( 1 ⁄ 3 R) All three coils in serial. Total resistance is tripled. (3 R) All four coils in parallel. Total resistance is quartered. ( 1 ⁄ 4 R) All four coils in serial. Total resistance is quadrupled. (4 R) Two coils in serial, connected in parallel to a second pair of serially connected coils. Or the other way around: Two coils in parallel, connected in serial to a second pair of parallelly connected coils. Total resistance is the same as for a single coil. (1 R)

Setup In a multi coil setup, all coils must be identical. Two coils in parallel. Total resistance is halved. ( 1 ⁄ 2 R) Two coils in serial. Total resistance is doubled. (2 R) All three coils in parallel. Total resistance is divided by three. ( 1 ⁄ 3 R) All three coils in serial. Total resistance is tripled. (3 R) All four coils in parallel. Total resistance is quartered. ( 1 ⁄ 4 R) All four coils in serial. Total resistance is quadrupled. (4 R) Two coils in serial, connected in parallel to a second pair of serially connected coils. Or the other way around: Two coils in parallel, connected in serial to a second pair of parallelly connected coils. Total resistance is the same as for a single coil. (1 R)

The distance between each "ridge" on the twisted wire. Use 0 for non-twisted wire (parallel strands). For improved accuracy: Count 10 ridges, measure their total width, and divide by 10.

Get started Start filling out the input fields from the top left. If you're American, you may want to switch to imperial units (inches instead of millimeters). If you're unsure about something, try leaving it at the default value. You can always correct it later if it turns out to be wrong. If you're new to coil winding, your wire is probably Kanthal A1, and it is probably round. Conveniently enough, these are the default values. The wire diameter should be printed on your spool, in either AWG or in millimeters. Enter this in the AWG field or the field to the immidiate right of this, labeled ⌀ r . Finally, select the target resistance of your choice. It is advisable to stay above one Ohm until you're fairly certain of what you're doing. You need to know how much current your batteries are capable of providing safely. Please read up on battery safety anyway, this stuff is important. As you update the input values, the results will be updated in the table on the right. Video tutorials English: Steam Engine Website Coil Wrapping Tutorial by UK Vape Community

Steam Engine Website Coil Wrapping Tutorial by UK Vape Community English: Tutorial - RDA Standard Dual Coil by Todd ecigreviews

Tutorial - RDA Standard Dual Coil by Todd ecigreviews English: Steam Engine SMPL Coil Build | VAPEFOG by Vapefog Reviews

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Review of Stream Engine by Gareth Witty Ελληνική: steam engine interview - παρουσιαση του steam engine υπολογιστη ( part 2 ) by VapeLikeGeek GR

Reading the results Resistance wire length This is the length of the resistance wire after you've installed it in your topper and trimmed the excess. Number of wraps If you're making a coil for an atomizer where both the coil legs point in the same direction, the "Number of wraps rounded to half wraps" is the result you want. If you're coiling for an atomizer where the legs point in the opposite direction, use the "Number of wraps rounded to full wraps" result. Heat flux Generally you want to stay somewhere between 120 and 350 mW/mm². Some like a cooler vape, others like it hot. The color of the flame icon will give you a rough idea. Adjust to your own taste. Heat capacity The higher the heat capacity, the slower your coil will be to heat up (and to cool down). Leg power loss Wasting power on heating the coil legs can make your vapor taste metallic or harsh, so keep your legs short whenever you can. Interestingly, the leg length is not the only value that affects the percentage of power loss in the legs. The wire gauge and the number of wraps also come into play, so keep an eye on this number. With most coils, you generally want to keep it below 10%. Advanced The rest of the result values will probably start to make sense once you get used to using the calculator. If you need an input option or a result that you haven't seen in Steam Engine yet, try clicking the Advanced button. You might be in luck. A second click on the button will bring you back to the basic mode. Note that any changes you made in the advanced mode will be remembered even if you exit the advanced view. If you want to start from scratch, use the Reset button.

How the coil calculator works – what it does, and what it doesn't do

Platform and precision of engine parts All calculations are done in JavaScript, which uses 64 bit floating point. This yields a precision of 15–17 significant decimal digits, which is more than sufficient for the purpose of modeling a coil build. Internally, all variables are stored and calculated in metric units. Unneccessary unit conversions are avoided in order to prevent accumulation of rounding errors when using imperial units. Three values are written to the input fields during use (advanced mode): Wire diameter, wire resistance per mm, and resistance wire length. These numbers are rounded in the input fields, but still preserved with full precision in memory. If you manually override a value, you can enter your own number with any precision you want. When you save, and subsequently load the settings, rounded values will be displayed, but the number will still exist with the full precision in memory.

Inner workings – a peek inside the engine room Resistance wire length AWG is converted to diameter by using the formula that defines AWG. This should make the AWG conversion more precise than the numbers stated by many resistance wire vendors. Wire resistance per unit length is determined by the resistivity of the wire material, and the cross section area of the wire. The resistivity for each material is looked up in a small table of constants. The resistance wire length is your set target resistance divided by the wire resistance per unit length. Leg length is subtracted before calculating the number of wraps. Material Resistivity (Ω mm²/ m ) Kanthal A1/APM 1.45 Kanthal A/AE/AF 1.39 Kanthal D 1.35 Nichrome N20 0.95 Nichrome N40 1.04 Nichrome N60 1.11 Nichrome N70 1.18 Nichrome N80 1.09 Ni200 0.096 (@ 20°C) Wraps When you input the inner diameter of the coil, the outer diameter is simply the inner diameter plus twice the wire thickness. The circumference of your coil is then by multiplying the outer diameter with π, and we have length of a single wrap. The wrap does not go in a straight circle around the mandrel, but rather in a helix, making it slightly longer than the coil circumference. For twisted coils, the 2–4 strands are combined into one diameter using the diameter of an outer circle encompassing the 2 4 tangent circles of each strand. Heat The heat flux is more or less evenly distributed over the resistance wire. Hot legs are undesirable, so the power used to heat the legs can be regarded as "lost". When you set a heat flux, the calculator will tell you what power/voltage your mod needs to output in order to achieve the desired heat flux. What heat flux to aim for depends on how long your puffs are, whether or not you preheat your coil, the heat capacity of the coil, type of e-liquid, airflow, wicking, personal taste, etc. The density of the coil material is used to calculate the wire mass and heat capacity. Because of lacking data on the density of different Nichrome alloys (except N80), the density of the Nichrome qualities are interpolated from the densities of the main alloy elements. The heat capacity of the wire materials does not vary much between the alloys used. Therefore 0.46 kJ kg-1 K-1 is used for all kanthal, and 0.447 kJ kg-1 K-1 is used for all nichrome.