How I Wind and Tin Toroids
For this exercise, assume you are right handed and will be using 24 gauge wire to wind on a T37-6 Toroid.
1...Determine the number of turns needed to achieve the desired inductance.
2...For a T37-6 toroid, the wire length is 0.5" per turn plus any extra lead-length required.
Most of the time we will want about 1" of lead coming from the body of the toroid. For a
ten turn toroid, cut a piece of 24 ga. magnet wire 7" long.
3...Hold the toroid in your left hand with your thumb and index finger so you're looking thru
4...With your right hand, insert the wire thru the toroid so that half of the total wire length
has passed thru the hole.
5...Now take your right hand index finger and thumb, squeeze the wire against
the toroid. With your left hand, take the end of the wire that comes out of the bottom and bring it
around the outside of the toroid, up towards you and feed it back thru the top of the toroid.
The wire should be passed thru the toroid twice at this point. Use your fingernails to push the wire
tight against the toroid, so that there is little space between the wire and the body of the toroid.
Keep the windings as tight as you can around the toroid. Repeat this step until you have only 1" of
6...Flip the toroid around so that the bottom hole is now the top hole, then repeat step 5.
7...Each wire coming from the toroid body should now be about 0.75 to 1.25 inches long.
1...The trick to tinning magnet wire is to find a GOOD WAY to remove the insulation first.
Some magnet wire will melt the insulation off as soon as it is heated. This stuff is easy to tin.
Just heat it with your solder pencil and apply solder at the same time. However, if you have the
other kind of wire, there is a method that I use to remove the insulation. Here's how.
2...Obtain a medium size and sharp pair of wire cutters, also called dikes by some electricians.
Some folks also call them side cutters. The best ones are cutters that have beveled jaws.
3...Hold the dikes in you right hand, placing your thumb on the side of one of the handles,
your index finger between the handles and the other three (I hope) fingers on the other handle.
4...Practice opening and closing the jaws of the dikes by moving your index finger up and down the
crotch of the dikes (no pun intended, sri). The idea here is to be able to insert a wire into the jaws
of the dikes and grabing it without nicking or cutting the wire.
5...After you are barely holding the wire in the crotch of the dikes, pull the wire thru the dikes
with your left hand, constantly monitoring the pressure of the jaws with your right hand. Repeat this
proceedure, rotating the wire in the jaws of the dikes.
6...With repeated practice, you should be able to strip some, most or all of the insulation off of
the wire. Once you have removed half or more of the insulation, you can tin the wire, which will
usually remove any remaining insulation.
7...When stripping and tinning toroid wires, strip and tin the wires all the way to the body of the toroid.
Many times the insulation is not stripped all the way to the body of the toroid, so when you insert this
wire into a PCB hole for soldering, the insulation is still on that part of the wire that penetrates
thru the PCB solder hole, NOT making a proper electrical connection.