Joule Thief

[TheNOP]

Yes, these are exactly the video courses I have been watching.  Dr. Walter Lewin is fantastic!  There are actually about 50 lectures in this series from the MIT website, and others.  I freely admit that the math part of this, which is a huge part, is beyond my current understanding.  He can go over my head about 5 minutes into the lectures but, I can then watch them again and again....sooner or later...something should sink in yes?

some maths parts are still over my head too, so don't worry too much about your current understanding.

those maths are not easy.
but, yes, watching them again and again will sink in.
even more if you take the time to learn side stuff like what sigma, kappa, omega, etc..., values are or what they define.

but for me, what is more important is the explanations, the examples, derive from those formulas.

[jadaro2600]

@TheNOP,

The DMM I have is a sears multimeter, they're cheap, have a diode test function and can take frequency measurements up to 10MHz...  I have one DMM which does the same thangs as the other, except it can also test transistors.  Although, it putts strange numbers out there...

Most any of the sears DMM's are cheap.

@jeanna,

Duty cycle is pulse duration ( time on ) divided by the pulse period  (waveform from peak to peak).  I'm guessing that the DMM does this math on it's own... ( from the frequency and the duty cycle ), I can get a rough estimate of the wave form, but only a stone-age estimate.

I tried to create a table, but the forum code would not work.  I will use highlight next time.

[electricme]

@TheNOP, Jadaro2600

Thankyou both, for bringing the Duty Cycle up, and explaining it so well.

Some of my past suggestions involve the Duty Cycle, but I put it differently, I am referring to the amount of time needed to fill a capacitor, then switching between that one and then filling another capacitor, then fill a number of them.
Then switch them all together and discharge them in one go.

  C1 fill time   ST C2 fill time ST C3 fill time ST C4 fill time   ST C5 fill time  ST C6 filll time ST C7 fill time   ST C8 fill time  ST DumpTime RT
/|-------------------|-|-------------------|-|-------------------|-|--------------------|-|--------------------|-|--------------------|-|--------------------|-|--------------------|-|---------------    |--\

/       =  each cycle begins (capacitor filling stages)
|-|     =  division of times which shows where the switching stages occur
C1-8 =  Tha actual time the control circuit is allowing that capacitor to fill, weather it be to 60%, or 70% or 80% or to 100% (controled by a Tank circuit)
ST    =  Switching State Times, between each capacitor reloads
DT    =  Dump Time, the time allowed to dump the contants of all capacitors together in one go, BOOM
RT    =  time allicated to begin the whole process again.
\       =  cycle ends, and a new cycle begins.





A Pulce Width Modulation power supply does the same thing to control the speed of a DC motor.
But this different to the raising or lowering voltage.


My TWV I posted a few pages back uses the same principle to give the effect of the LEDS going round and round, but its circuit switched the LED ON, for a certain time, then the next LED is switched on and so it continues for eva.

Confession time 4 me, I had heard of the Duty Cycle years ago, but I forgot it, if that seems silly, but it happened, so thanks to Jeanna for asking her question "What is the Duty Cycle?"

@ TheNOP,
If you have a mobile ph (don't answer that), then use the camera function to post a photo of your JT, this is how I make all my photo and Tiny Videos posts here.
To those who have a very good grounding in the electronics fields, and are able to run rings around us others with your knowledge/explinations, and we know it took you years to accumilate this wealth of knowledge, but there are others here who havent any ideas on what it is exactly you may be talking about, (and are confused easily by new termiinology) so if you could give just the very basic explination in simple ways, then us (me) slow learners would have a betta chance of understanding it.

I see Bills drinking bird now very differently, as a Mechanical and electrical variable Duty Cycle controlled by "temperature" and "fuel" (water) and mother nature.

jim

[jeanna]

Ok I made this schematic.With my mod of taking out the resistor. And only 6 paired winds on the torrid cuz that is all that would fit with 26 awg wire.
http://www.postimage.org/image.php?v=gx1fn9VA

Then i put 15 White LED's on and used a 68 OHM resistor for the reading. As you can see it says .9 Volts / 68 Ohm resistance = 13.2 Milliamp draw.
http://www.postimage.org/image.php?v=gx1fn7qr

Nice job, dog812,


So, what do you think about a secondary ?

Do you think you could drive leds from a secondary off your toroid? Maybe it would only use half of what you are using!

Good going,

jeanna

[dog812]

Nice job, dog812,


So, what do you think about a secondary ?

Do you think you could drive leds from a secondary off your toroid? Maybe it would only use half of what you are using!

Good going,

jeanna

I would but there was no more room on the torrid.. ill have to use smaller wire.
I was trying to keep it simple , for my hula hoop design.. so i can keep the labor costs down.  One of these days ill make a JT'd hoop.

Do you thinki could keep the 6 paired winds with a 20 wind secondary? or would i need to add more then 6? Will the secondary just not work if there is not enough primary winds?