Joule Thief

[TheNOP]

Why does my toroid sing?

because of induction.

if you want to atenuate it, dip your toroid in melted wax and let it cool down.
glue, shelac and other similar things, like varnish can also be use.

[jadaro2600]

Thankyou - know any good places to bet wire varnish? ...this stuff needs to be as temperature dependable as possible.

[TheNOP]

for those wanting to make their own iron cores, here is the way i used.

you will need:
-a pipe, the size you want/need, any kind, as long as it is rigid.
-a sheet of paper, not needed if your pipe is a cardboard type, toilet paper core is not rigid enough unless your wire is really thin.
-tape, any kind, electrical tape do fine.
-super glue, cyanoacrilic, fast curing type
-garden wire or similar insulated iron wire
-something thin that won't burn easily, the thinner the better.
-a welding machine, spot welder are automotive welder type.



-put the paper sheet around the pipe, tape it so you can remove it from the pipe later.

-keep some wire length to be able to weld the ends together.
length depend on the thickness of your core but can be cut later.
bend it at 90 degree and tape that wire length to the paper

-make one turn, this turn must be as strait as possible around the pipe
tight it and glue it with super glue, let it dry.

-add more turns, but glue the wire every 1/4 turn to the one already turned.
one drop was enough for me, no need to glue it all the 1/4 length.
to make sure it won't deform, you can later dip it in varnish if you want.

-add as many layers as you want/need.
make sure you keep enough wire to be able to weld it to the other end.

-put something, as thin as possible, that will not burn, where the 2 ends will meet.
like thin fiberglass cloth or leather.
i used thin flexible fiberglass circuit board, about 1/64 thick without the copper on it.

-weld the 2 ends together

it does a better job if the layers are paired as the ends will be on the same side.
make sure you will be able to get your core off the pipe easily, double check the pipe ends and sand them if needed.

the gluing process is time consuming, have patience, it will pay off.

[TheNOP]

Thankyou - know any good places to bet wire varnish? ...this stuff needs to be as temperature dependable as possible.

shelac was/is also used/use for electrical insulation.

[jadaro2600]

shelac was/is also used/use for electrical insulation.

Have you a picture of your core?