By Papa Bale · April 5, 2026
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Wire gauge is one of the most debated topics in the pulse motor community, and for good reason — it directly affects how your motor performs. Get it wrong and your coil either heats up excessively, lacks the magnetic field strength you need, or simply won't fit on your former. I've wound coils with multiple wire sizes and I want to share what I've actually learned, not just theory.
In a pulse motor, the coil performs two jobs: it generates a magnetic field when pulsed, and it collapses that field to produce back EMF. The wire gauge affects:
Here's a quick comparison of the gauges most commonly used for pulse motor coil winding:
16 AWG — Diameter: 1.29mm | Resistance: ~13Ω/1000ft | Current: up to 13A continuous
Best for: High-current builds, lower voltage supplies, maximum electromagnetic force per pulse
20 AWG — Diameter: 0.81mm | Resistance: ~33Ω/1000ft | Current: up to 5A continuous
Best for: Mid-range builds, good balance of turns count and current capacity
22 AWG — Diameter: 0.64mm | Resistance: ~52Ω/1000ft | Current: up to 3A continuous
Best for: High-turn-count coils, higher voltage supplies, maximizing BEMF spike voltage
24–28 AWG — Very fine wire, high resistance
Best for: Trigger/feedback coils in Bedini SSG designs, not main drive coils
My most-viewed pulse motor video features a 16AWG coil, and there's a reason for that. When I was designing a budget-friendly, beginner-accessible build, I wanted a wire that was forgiving — easy to handle, easy to wind without kinking, and capable of passing enough current to generate a serious magnetic punch even from a 12V battery.
16AWG magnet wire is thick enough that a beginner can wind it without frustration. It has low enough resistance that you don't need a high-voltage supply. And the resulting coil produces a satisfying electromagnetic kick that gets the rotor spinning reliably. The tradeoff: you won't fit as many turns on a given former, so your inductance is lower and your back EMF voltage spikes are more modest. For most builds, that's fine.
Thinner wire shines when you want to maximize your turn count and you're running from a higher voltage supply (24V–48V). With 500+ turns of 22AWG, you get significant inductance and higher BEMF spikes — which means more recoverable energy per pulse. If back EMF recovery is your main goal, a higher-turn fine-wire coil is worth the more tedious winding process.
The downside: thin wire is harder to wind uniformly, kinks easily, and has higher resistance meaning more heat per amp. You also need to be more careful about transistor current ratings. See my transistor guide for matching the right transistor to your coil.
Bifilar coils (two wires wound simultaneously) add another consideration. See my coil winding guide for the full treatment, but briefly: when winding bifilar, you're doubling the wire in the coil window, so you need to size each wire one or two gauges thinner to maintain the same turn count. A bifilar 22AWG is roughly equivalent in fill to a single-wire 20AWG.
A common question among advanced builders is whether to use litz wire instead of standard solid magnet wire. Here's what you need to know:
Litz wire consists of many thin, individually insulated strands woven together. Unlike single-strand wire, litz wire reduces the "skin effect" — the tendency of high-frequency currents to flow only near the surface of a conductor. In pulse motor applications where the coil switches rapidly, this can matter.
See our detailed 26AWG litz wire voltage guide for specific measurements and comparisons.
The resistance of your coil directly affects how much current flows and how much heat is generated. Here's a practical guide:
12V Drive Coil with 2N3055:
Target: 1-5 ohms
Current: ~1-4A (within transistor limits)
Good for: Standard Bedini SSG builds
12V Drive Coil with TIP31C:
Target: 3-10 ohms
Current: ~0.5-2A (safer for smaller transistor)
Good for: Beginner builds, lower power
24V System:
Target: 5-15 ohms
Allows higher turn count for more inductance
Good for: Advanced BEMF recovery setups
The number of turns you can fit depends on wire gauge and bobbin size. As a rough estimate:
Multiply by the number of layers you plan to wind. Remember: more turns = more inductance = higher back EMF voltage, but also higher resistance.
| AWG | Diameter | Resistance/1000ft | Max Current | Best Use Case |
|---|---|---|---|---|
| 14 AWG | 1.63mm | 2.5Ω | 15A | Heavy-duty drive coils |
| 16 AWG | 1.29mm | 4.0Ω | 10A | High-power drive coils |
| 18 AWG | 1.02mm | 6.4Ω | 7A | Medium-power drives |
| 20 AWG | 0.81mm | 10.2Ω | 5A | Best all-around choice |
| 22 AWG | 0.64mm | 16.1Ω | 3A | High-turn drive/trigger |
| 24 AWG | 0.51mm | 25.7Ω | 2A | Trigger coils, pickup |
| 26 AWG | 0.40mm | 40.8Ω | 1.5A | High-voltage pickup |
| 28 AWG | 0.32mm | 65.3Ω | 1A | Bedini SSG trigger |
Wire that's too thin for your application will have high resistance, limiting current flow and generating excess heat. The coil may get warm or hot during operation, and the magnetic field strength will be weaker than expected. In extreme cases, the wire insulation can melt. If your coil runs hot, consider using thicker wire or reducing the number of turns.
Yes — in fact, this is common in advanced pulse motor designs. You might use 16AWG for the main drive winding (high current, strong magnetic field) and 26AWG for a trigger winding (high turns, sensitive to flux changes). In bifilar windings, both wires are typically the same gauge, but some builders experiment with different gauges for each strand.
Indirectly, yes. Thinner wire allows more turns in the same space, which increases inductance. Higher inductance produces higher back EMF voltage spikes when the transistor switches off. So while the wire gauge itself doesn't directly affect back EMF, the turn count it enables does. For maximum back EMF recovery, many builders use 22-26AWG to maximize turn count.
Magnet wire is available from electronics suppliers like Digi-Key, Mouser, and Jameco. For hobby quantities, Amazon and eBay offer good prices. Look for "enameled copper magnet wire" — the enamel insulation is essential for preventing short circuits between turns. Buy more than you think you need; you'll use it for multiple projects.
Standard magnet wire has a 130°C (Class B) or 155°C (Class F) temperature rating, which is sufficient for most pulse motor applications. If you're building a high-power motor that may run warm, consider 180°C (Class H) rated wire for extra safety margin. The temperature rating is marked on the wire spool or datasheet.
For your first pulse motor coil: start with 20AWG. It's the golden middle — manageable to wind, enough turns for reasonable inductance, and current capacity sufficient for most 12V builds. Once you understand how your motor responds to coil changes, experiment with 16AWG for raw power or 22AWG for higher BEMF voltage.
Whatever you choose, wind it tightly, evenly, and secure it well. Sloppy winding wastes more performance than wire gauge choice ever will.
See the full 16AWG pulse motor build on YouTube — real parts, real results, no fluff.