Joule Thief

[dog812]

Thanks for all the info on resistors ... and everything else.. I never would have figured this stuff out if i didnt find this site.

OK.. so testing my current draw.. i think i am doing this right.. I have the red wire in the spot that says 10A

When i test it with 1k resistor in :  3.2 - 3.4   with noticeable less light.

2.2k resistor : 3.2 - 3.4 same amount of light.

resistor out : around 3.7 2x brighter.

5k pot : 3.6  same brightness with no resistor.

using the extra 22N cap method.

[dog812]

P.s.
when it says 3.6 what does that mean? since its on the setting of 10A do i x10?
What unit is that in? milliamps?

[Thaelin]

   If you look at the tech sheet on the transistor, you will see an entry that
deals with the base junction. The resistor is there to limit the amount of current
that flows through this junction. Too much and you kill it. The more current
you let flow through, the more power that is allowed to flow from emitter to
collector or vise versa depending if npn or pnp. Since we are using only 1.5v here
the transistor is capable of handleing it. The 3904 is a general purpose switching
transistor widely used in old equipment.
   Now when you start upping the voltage, look out as it will smoke them quick, I know.
Would be a good rule to not go below 10 ohms at 1.5v just for safety reasons. I
have seen people use 10 ohms on a 3055 at 12v and that is really pushing it hard.
Using ohms law, you can figure how much to add for the voltage used. Specs say it
breaks down at 6 volts, but remember you are inducing it from a kick back from the
coils too.

thaelin

[jadaro2600]

This is a drone post, .

I got some new parts today, and decided to demonstrate a proof of concept.  Circuit diagram is included, along with two pictures.

I'm NOT using a resistor, only a capacitor, and an axially molded inductor of 15 micro Henrie which contains ferromagnetic material around which is a larger coil.  This simple setup produces 7.5 volts at the test side, without an LED present.

These two elements, or some similar element setup is all that is needed to begin the oscillation process.  This particular setup is running at around 2.5MHz...tomorrow, I will attempt to run many led's off this one circuit.  Then later, I will be using this setup to turn on the oscillations - isolating the blocking oscillation action to this particular two-piece setup, thus freeing up the toroid for primary and secondary winding or some other setup.

The pictured circuit is extremely sensitive, ..in order for it to start, the main capacitor must be completely discharged.  I'm not able to insert an ammeter - it simply will not cut on with it in the circuit.

*edit: I was able to light 5 LEDs before the circuit started dimming...after 9 things were still lighting up, but not so well.

[Pirate88179]

@ Jadaro:

Nice work!  This is very interesting and needs to be looked into further.  This goes along with my original thinking of not liking resistors.  Thanks for posting this.

Bill