A homework question for my Electromagnetic Fields and Waves course asks, How would you build a 0.1H inductor? I am extremely stuck! I have researched and tried to figure this out but I am having no luck. My classmates are having trouble as well. Please help!
Let me split your question into two parts. How do you build an inductor? How to make it 0.1H? Building an inductor is very simple. Wind a few turns of wire and you have an air cored inductor. That means, you basically need two things to build an inductor. A conductor having a certain number of turns and a core. The core can be air, silicon steel, nickel, soft ferrite, hard ferrite, powdered iron How to make it 0.1 Henry (100mH)? So an inductor has a certain inductance. The inductance depends on the number of turns and the material of the core. Apart from the two, you need to know the following factors: 1. Current through the conductor, 2. Type, size, area and permeability of the core 3. The frequency of operation. The current is important, because it should not saturate the core. Read info regarding the B/H curve. To keep it simple, for a single layer AIR CORED INDUCTOR the formula is: L ((r^2)(N^2)) / (9r+10l) where L is inductance in microhenrys, r is radius of coil in inches, l is the length of coil in inches, and N is the number of turns in the coil.
Since this is for a class, I think all they want is a general answer. 100 mH, you would generally use an iron or ferrite core. This would most commonly be a rod or torroid, but other configurations exist. You can find formulae on the internet for the inductance of various topologies. If the inductor didn't have to carry much current, or need to have a high Q, you could use very fine wire, and the whole thing would be the size of a joint of your finger. If it had to carry a lot of current, it might be the size of your fist.
Use a large ferrite torroid and wind it out of solid copper magnet wire. Get the torroid from an electronic scrap sales.you could also use a ferrite rod for the core. Ferrite rod or torroid will keep down the amount of wire necessry to wind it. the wire size will determine the current handling capability.
