Author Topic: Joule Thief (Read 6336334 times)

xee2 · « **Reply #10965 on:** December 21, 2009, 07:43:50 PM »

The previous circuit I posted for measuring the JT output power had a safety problem because if the resistor was ever not connected across the capacitor (even for just an instant) the capacitor would charge up to the full open circuit output voltage of the pickup coil which might be well over 1000 volts. Even small capacitors charged to over 1000 volts can be dangerous. As long as the resistor was never disconnected, the capacitor voltage would stay under 50 volts and was not so dangerous. To prevent the capacitors from charging to over 100 volts I have added the neon bulb. The neon bulb remain off until the voltage across the capacitor reaches about 100 volts. Thus in normal operation the neon bulb does not change any measurements. But now, in order for the capacitors to charge up to the full output voltage of the open circuit pickup coil, both the resistor and the neon would have to be simultaneously disconnected from the capacitor. Thus there is a much smaller chance that the capacitor will ever charge to dangerous levels. If the voltage across the capacitor ever trys to go over 100 volts the neon will turn on and prevent the voltage from going over 100 volts.

jeanna · « **Reply #10966 on:** December 21, 2009, 08:48:39 PM »

xee2,
This whole thing is so confusing.
Putting the neon in the secondary might limit the v to 100 (or 170 spiky volts, more likely,) but the thing is it will limit it and it is the volts you are measuring to use in the ohms law based formula.
I have issues with using ohms law with ac or pulsed dc, but besides those objections, how on earth are you ever going to see a volts reading that is above what the neon siphons out?

I don't get it??

thank you,

jeanna

innovation_station · « **Reply #10967 on:** December 21, 2009, 09:40:35 PM »

thank you guys..

now any one with 2 wits about them can put it togather ...

any how be careful...

so i will explain ...

just as i have showen .. in my most recient videos ...

i have 2 outputs ...1 normal jt spikes used to charge a low voltage cap 2 many powerful spikes ... ment to charge output caps..

this can be configured many ways ... meaning stright through ou put ... this means insted of recharge ... BOTH ARE SENT TO FILIMENT BULB...

thank you

william

heres the scope ... kids are over for a few days im cleaning up then we are building and makeing videos ... this means ... all 3 of us ...

anyhow .. i have those ramma chasers .. still i will use those to conrtol fets to flip flop between low and high for a basic unit i will use the ramma toy to sub a relay or other switching means ...

i can charge caps and allow them to release or i can probally drive loads .... never publically tryed yet ...

l8r

xee2 · « **Reply #10968 on:** December 21, 2009, 10:50:32 PM »

@ jeanna

Quote from: jeanna on December 21, 2009, 08:48:39 PM

xee2,
This whole thing is so confusing.
Putting the neon in the secondary might limit the v to 100 (or 170 spiky volts, more likely,) but the thing is it will limit it and it is the volts you are measuring to use in the ohms law based formula.
I have issues with using ohms law with ac or pulsed dc, but besides those objections, how on earth are you ever going to see a volts reading that is above what the neon siphons out?

I don't get it??

thank you,

jeanna

The diode and the capacitor make a half wave rectifier, so there is DC coming out of the capacitor. The voltage across the resistor will always be less than 100 volts because it would take a lot more current than the JT can supply to get the voltage across a 10K resistor higher than that (remember, E = I x R). The voltage increases until the JT can no longer supply more current. That is the point I am trying to find. Since the voltage does not ever get to 100 volts, the neons never turns on - it is just there for safety.

You can see what is happening on your scope by just putting a resistor across the outputs of the pickup coil and then looking at the AC voltage across the resistor with the scope. Make sure that resistor stays connected or you will blow your scope. Start with a 10K resistor. Next use a 1K resistor. You will see that as the resistor value decreases so does the voltage across it. At the limit of a zero ohm resistor there will be zero volts across it.

I hope that helps

xee2 · « **Reply #10969 on:** December 22, 2009, 12:00:46 AM »

I have made a 2B-10C-250P coil on 3.38" toroid. I sprayed the core with clear plastic and used wire wrap wire. No problems with shorts (yet). I have just started doing tests. But it does not seem to put out as much power as the coil with 80 turn pickup. More later.

tysb3 · « **Reply #10970 on:** December 22, 2009, 01:27:30 AM »

Hi,
now I have my toys, and Im playing

I improve my driwe. But I dont have oscioloscope to adjust capacitors for biggest aplitude on diods.
my JT now running about 1 hour and dont drop voltage, stay same 1.274 V
Im waiting for my camera deliveri.
after Ill post pictures

tysb3 · « **Reply #10971 on:** December 22, 2009, 01:39:39 AM »

sorry, I lose diode on drive

innovation_station · « **Reply #10972 on:** December 22, 2009, 02:14:15 AM »

ok i have up graded my transistor to 3055 and gadgetmall standard aa

2500mah and i will SAY HEAT SYNC IS A MUST !

the darn thing gets hot! and it does its job well .. im working out some kind of switching thing and 2 caps .. 1 to recharge source battery and 1 to charge out caps ...

ist

i have found there is a delicate ballance of EXTERNAL APPLYED MAGNETICS and the location and polarity ... make a big diff ... i change my freq of my entire set up by changeing where the neo is placed... my spikes get bigger with more freq .... lol

so it seams to be a GAIN GAIN game..

xee2 · « **Reply #10973 on:** December 22, 2009, 02:23:05 AM »

Quote from: tysb3 on December 22, 2009, 01:27:30 AM

my JT now running about 1 hour and dont drop voltage, stay same 1,274 V

I assume you mean the battery voltage stays at 1.274 volts. If you are getting one thousand volt output then I think you have done something amazing because that is hard to do with a 19 turn JT. Good luch with your tests.

tysb3 · « **Reply #10974 on:** December 22, 2009, 02:49:13 AM »

@ xee2
yes rech. battery on running JT, now climbing to 1.275 v

xee2 · « **Reply #10975 on:** December 22, 2009, 03:08:46 AM »

The first testing with my new coil is disappointing. The output voltage is only a little over 1000 volts and the CFL is hardly any brighter than with the 80 turn pickup coil (but it does seem a bit brighter). I need to figure out why the output voltage is not higher.

Pirate88179 · « **Reply #10976 on:** December 22, 2009, 03:17:13 AM »

Xee2:

Welcome to my world. Your light (given the differences in exposures from cameras) appears to be about as bright as mine. Remember I used 2 toroids stacked together so when I wound 330 turns (give or take) I have a lot more wire there than on a single toroid.

When I see Jeanna's, and others photos, i am thinking, why did I use 2 toroids and all that wire as this does not seem any brighter, and maybe not even as bright, as what they are doing.

So, at this time, I can not recommend using 2 toroids as I have not seen a huge gain from this, or any gain really. I am not done tuning yet but, I don't see it being a big breakthrough at this point. I was just glad to be able to be shocked by it when I was not before. But, maybe this lower freq. is not what we want? I would guess that the lower freq. will allow longer battery life as it is not turning on and off so fast but, I really don't know.

Later, when I get back from a job, I will continue with my tuning and see what happens. I don't expect any order of magnitude increases though.

Bill

tysb3 · « **Reply #10977 on:** December 22, 2009, 04:30:40 AM »

now climbing to 1.276V.
the battary NI-CD AA700mAh recharge itself !!!!!!!!!!!!
I cant belive my eys. all parts from tv, from skip. I have only multimetter, breadbord and soldering tools.
I cant ajust properly it, but its gooooooooo

kooler · « **Reply #10978 on:** December 22, 2009, 04:34:51 AM »

tysb3
i think i might build your circuit.. if you don't mind
i tried the same feedback on my second stage of my circuit .. but it puts out to much
it over runs the rest of my primany circuit.. burning the tansistor
i like what i see on your circuit.. what r the cap values at the feedback...
thanks

tysb3 · « **Reply #10979 on:** December 22, 2009, 04:55:13 AM »

@ kooler

from picup coil capacitor is M .55J,
from collector 10.0 mkf

its need to play with this caps to inproove JT

transistor is D1885 from tv line transformer

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Author Topic: Joule Thief (Read 6336334 times)

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