Rev 1.03
10
When you have unwound the wire and straightened it, cut it into three approximately equal pieces.
These three pieces now need to be tightly twisted together to make the trifilar wire. My method for
this is to tie one end in a knot around a small screwdriver shaft. Similarly tie the other end around
another small screwdriver. Now clamp one end somehow to something solid. You could use a
vice, if you have one. If you don’t, then you have to get creative and think of something. Here I
taped it to the edge of the desk. Now you can twist the screwdriver at the free end, repeatedly until
you twist the three wires together thoroughly. You need to keep the wire under a little tension to
keep the twists evenly spaced.
I put about 70-90 twists into a 25cm
length of wire. The end result is
something like the photo (right). The
measurement scale is in cm.
Now cut off the untidy ends, and this is
the piece of wire that will be used to
wind the FT50-43 toroidal core as a
trifilar transformer.
