TRANSFORMERS AND INDUCTORS
Next, wind the toroids, beginning with L1.
Locate the three toroids, and the 22AWG magnet wire – the heavier gauge of
the pieces supplied. Cut a 20” piece from it. Take one of the toroids, and wind
21 turns around it with the wire. Remember that turns are counted as the
number of times the wire passes through the center of the toroid. Space the
turns evenly around the core. It is essential that the turns are pulled snugly
around the toroid, so that there is no slack between the wire and core. When
complete, strip and tin the wire ends prior to inserting on the PC board. Cut the
wire ends to about 1/2”.
There are a number of methods for stripping the insulation from magnet wire.
The wire provided in the kit is thermally strippable. If you have a higher wattage
or thermostatically controlled soldering iron, the heat from this (at least 750
degrees F) will be sufficient to strip the insulation from the wire. Alternately,
insulation may be removed using sandpaper of a a sharp hobby knife, prior to
tinning.
With the leads of the leads stripped, mount the toroid to the board, making sure
the leads are pulled snug from the back of the board. After soldering, inspect the
joints closely to be certain of a good joint. Resolder the joints if necessary.
[ ] L1 – 21 turns on T50-2
Inductor L2 is constructed in the same way using the remaining 22AWG wire,
but with 12 turns. Strip the leads, and mount to the board.
[ ] L2 - 12 turns on T50-2
Transformer T1 is constructed next. It is wound with three windings, two
primaries and one secondary, of 12 turns each. There are three pieces of
26AWG magnet wire provided, each a different color to help keep windings
straight. Two will be 10” long, and the other much longer. Cut a 10” piece from
the longer piece.
Wind each of the three wires twelve turns on the core, one at a time. When
finished it should look like the picture below. Double check that each wire has
the 12 turns, and that the order of the colors is the same at start and finish. Strip
the insulation from the windings, and install on the board. Pull the leads firm
from the rear of the board to assure the winds are snug on the toroid.
