# More winds or less winds on a toroid?

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#### smanches

##### New Member
I'm winding a toroid for a boost converter and from the two available cores that I have, one would need 8 turns the other 49 turns. Which would be better?

Is there a bottom limit on the number of turns, or is a single turn still a viable coil?

#### dknguyen

##### Well-Known Member
More windings means higher inductance but less current capability. Depends on what you need.

#### smanches

##### New Member
Both winds will give me 189uH since they are different types of cores, but you have a good point on resistance. I think I'll try the 8 turn wind first. It'll also be easier to wind.

#### kchriste

##### New Member
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It has much more to do with core saturation than wire resistance. The more turns you have, the lower the current at which the core will saturate.

#### smanches

##### New Member
That's a point I didn't think about at all. Not sure how to calculate it though, and will have to do some research.

One core has a saturation flux of 4300 (8 turns); the other is 2350 (49 turns). I'd guess I'm still better with the 8 turn core.

#### Leftyretro

##### New Member
That's a point I didn't think about at all. Not sure how to calculate it though, and will have to do some research.

One core has a saturation flux of 4300 (8 turns); the other is 2350 (49 turns). I'd guess I'm still better with the 8 turn core.
Sounds good to me, but the real answer might be that either would work equally as well. It really depends on the peak switching current levels required for the circuit. Once you know what the peak current demands are you should then be able to calculate if it approaches the core saturation levels of either core. It is possible that neither core will work if the current demand is too high. With incomplete data only guesses, hunches or assumptions are being made. It is first and foremost a calculatable engineering task.

Lefty

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#### smanches

##### New Member
I know the peak current (7.66A), but don't know the formulas for calculating saturation current yet. From the datasheet I have on the cores though, I'd guess that particular one would have a tough time reaching saturation with only 8 turns.

#### colin55

##### Well-Known Member
Wind them both. I think the 49 turn inductor will perform better. But I want you to test them and let me know. It all depends on the current and the voltage you are wanting to produce in the boost circuit (as well as all the other factors).

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