Below are Jim's detailed instructions for making a JT. This will help many of the new folks here and possibly quite a few of the rest of us. Thank you Jim for allowing me to post these here. Also, thanks Gary for suggesting that I do so.
Bill
"I have been quietly reading (whilst eating all my Licorice) and are aware of your problem trying to get your JT LED lit.
Just like you, I also managed to muck up most of my JT's bigtime, and it drove me crasy and set me back for weeks.
I found I was making a very basic mistake, I was connecting the bifilar wires back to front.
Why, because this is very easy to do, and it really has never been explained in very clear instructions, so I stumbled around in winding my torids.
The circuit as it is drawn is correct, BUT, it is deceiving because if one dosent know the reason for the DOT at the windings, there is no way they could work it out. It is in fact a lasy way to draw the circuit, so the circuit can be presented to look nice.
If the bottom lead, of the 2nd bifilar coil was drawn with it's lead going back upwards to the top of the other coil (batt +), and the top lead of the same coil, was drawn to go downwards, then it would make better sence.
The 2 black dots, means these are the ends of the 2 wires (the starts) which you held when you began to wind your coil.
If a beginner starts to make a bifilar coil, using same size and colour wires, it will probably not work, unless it's a fluke, and if it will not work, then the coil builder is left with, WHERE DID I GO WRONG, there are 7 connections, which compounds to at least 7X 7 = 49 different configurations or mistakes that are possible.
The easiest way to learn to make the bifilar coil and connect it's wire connections is to first have 2 different coloured wires to start out with.
Cut 2 lengths of insulated wires, and put a small tag you can write on.
Lets say one wire is GOLD, the other is GREEN.
With the "start" wires, mark them Gold (a) and Green (a) NOTE, these have the BLACK DOT's on the circuit
OK, TIME TO START TO WIND THE COILS.
Wind, wind wind wind wind wind lol
The end Gold wire is marked Gold (b)
The end Green wire is marked Green (b)
Now connect the Gold (b) wire to the Green (a) wire.
NOTE (This soldered connection is where you feed the (+) Positave from the battery).
The other 2 free wires are connected to the transistor and the LED like this.
The Gold (a) wire, is soldered to the COLLECTOR of the transistor.
The Green (b) wire is soldered to the RESISTOR 1k ohm
The other end of the resistor is soldered to the BASE of the transistor.
Now hold the transistor with the flat face towards you.
The middle leg is the Base (b)
The Left leg is the collector (c)
The Right leg is the Emitter (e)
Now look at the LED, there is a FLAT edge at the bottom of the LED
Twist the LED so the "flat" edge is to the right
Solder the flat or right leg of the LED to the right leg (e) of the transistor.
Solder the free leg of the LED to the collector (c) of the transistor.
Solder a black wire which is the NEGative to the Transistor (e)
Solder a RED wire to the wires on the torid you joined together.
Connect the 1.2v battery and it should light up.
OK, I hope this has shed some light on how to make it all work."
