Joule Thief

[altrez]

I did take out the led for every test. I only used the led to verify that the JT is working. I then remove it and test the pick up coil. After a full morning of testing I have still had no success with a pickup coil. I have now built 12 JT's lol they all work fine but not one will work power a pickup coil.

Thanks!

[hazens1]

Remember that for the pick up coil to work you must take out any LEDs you have connected between the ground and the collector.

Jesus

No.. In more than half the variations I have tried, I have gotten both the transistor and secondary(pickup coil) leds to light at the same time.

[jonnydavro]

@altrez.Hi.Can you put your ampmeter in series with the battery.If so what are the readings when-
1.Normal JT led in place
2.After removal off Normal JT led .Do not replace it for tests 3/4
3.Secondary coil open circuit
4 secondary coil with led
This will give us a clearer picture what is going on in your circuit.
                                                                                          regards jonnydavro

[resonanceman]

For a mold you could use wax and carve the shape in it, then remelt it to make a new mold if it gets damaged.
I'm not sure if the resin will get hot enough to melt the wax while curing though. Never tried it.
Or you could use some type of plaster or clay material. Drywall mud is quite cheap.
I would build a large mold with many cores in it so I only need to mix the resin and magnetite once.

Addendum: Here is a link on this forum on making magnetite cores. What an awsome forum we have here!
http://www.overunity.com/index.php?topic=3318.380

AbbaRue

Wax should  work well  for  molds as long as the  cores are small .

The  curing  process  of fiberglass resin  creates  heat. With  small parts that heat is  dissipated quickly..
Large parts can overheat .   1 inch thick  is  a common  limit  for  size ......maybe  it would  have to be  thinner  when using a wax mold.

Another  possibility  for molds is  silicone  rubber
I have used it  for molds before , the  difficulty is  in making the mold  so that  it  does  not  squash   the silicone   when  it is  being held in place to poor the  resin.


If  you are  using  just enough  resin   to bind the magnetite particles together  the heat may not be an issue  at all ......the  magnetite  will  absorb much  of it .


If  you  find   your cores  have to much  magnetite  I would suggest  a filler  ......  Portland Cement has been used  as a filler in Epoxy resin for  some  applications  such as  restoration  of   buildings .


hope this helps   


gary

[TheNOP]

i have a coil that has 20 turns going the the Base/trigger and 70 turns going to the Collector/power. what i get with a 10 k ohm base resistor is .64 volts at the base and i get 1.03 volts at the collector. the bat voltage is 1.05 with no connection. the amp draw is .06 ma. that is the only coils of wire on this torrid the trans is a 3904.
with a 2222 trans i have to switch the base and collector wires and the base voltage using the same coil now has a base voltage of .04 and the collector is now 1.04 volts and the led is not as bright with this trans. the amp draw is now .09 ma.

so i am getting a better performace from the 3904. i wanted the highest voltage on the collector before adding a secondary to it

what you see is not always what you think it is.

this is showing you that both transistor have a bit different base triggering threshole voltage.
you can often see the same thing with two same part number that were not manufatured at same time(different batches) or not by same manufacturer.
since your coils are not the same size, the bigger coils get a greater potential difference compaire to the smaller one.

i suggest using a potentiometer instead of a fixed resistor.
you will get better result when adjusting the base resistor, with both transistors.

I took 3 different nails of 3 different sizes. I made the JT circuit and it works fine I can light all my LEDS with it. However I can not get a pickup coil to work with the nails either.

there is a possibility that your transistor is not cconnected properly, collector/emiter.

just in case.
are your leds 3v type ?
if not, your jt might not be working at all...
try to light one directly from the battery to make sure.
if they light, put 2 or 3 in series, add one until the battery can't light them.

and the third coil is not connected to any of the jt connections, it is only using induction to work.