Greetings,

Iam trying to make an air core coil inductor of 0.1 uH, with an 0.6mm wire. I tried this site calculator but when I compared it to other calculators (links below) I'm getting different results with same inputs in each. Which one is correct ?

https://www.allaboutcircuits.com/tools/coil-inductance-calculator/
http://www.daycounter.com/Calculators/Air-Core-Inductor-Calculator.phtml
https://rimstar.org/science_electronics_projects/coil_design_inductance.htm

 

None of them are 'correct'.
All such formulae are simply approximations.

 

None of them are 'correct'.
All such formulae are simply approximations.

I see, would you please tell me which one would be closer to the value i want ?

 

It all depends on the form factor of the coil.
What diameter is the coil to be?
Are you close winding the coil (each turn tightly next to the previous turn)?

 

It all depends on the form factor of the coil.
What diameter is the coil to be?
Are you close winding the coil (each turn tightly next to the previous turn)?

0.26 inches or 6.55mm, each turn is close to another by slight distance (0.4mm), i winded the wire on a 0.25 inch bolt.

 

All those formulae give number of turns around 3 to 4. As you can't really do a coil of 3.6 turns probably the best way is to use 4 turns and then measure the inductance and stretch or squish the coil to get the desired value.