Joule Thief

[TheNOP]

@PowerJunkie

the best way to connect your jts in a car would be to make a 1.2 volts power supply for them.
it is really easy to do one, you can search the internet for schematic.

use a LM317 or a LM337 regulator, a resistor or a potentiometer, a diode and 2 capacitors.
you can feed them with up to 48 volts and they give out between 1.2 and 37 volts, or 1.5 volts less then the input if the input is less then 37 volts.

the diode and one of the cap are not nescessary but they will help filter the jt's noise.

[TheNOP]

@Pirate88179

inserting in the first post, without deleting what is currently in it, look like a good idea.

[PowerJunkie]

Thanks to the replies to both of you! I know that I made it right and wound it right since it's lighting up a 3.6V White LED from nearly dead 0.9V AA battery. The issue I'm having is that it's not lighting up when it's connected to a 2V or 2.5V power source in the engine compartment, yet works with a 0.9V AA battery.

The sensor voltage is a constant 2V or 2.5V DC. I'm assuming the sensors provide at least 10 mA since the 2.1V Green LED will light up if I touch the raw leads on to the wires. It lights, but it's a bit dim. Why would you not recommend connecting it to a car engine sensor? The sensors I'm trying to hook up is the Mass Air Flow and Throttle Body sensors. I'll be switching out to dual intakes (which will be including larger Mass Air Flow sensors and Throttle Body senors on each intake) and I'm making this so that I know if the secondary intake is active.

I'm pulling out my hair here since it work beautifully with a nearly-dead battery but not on the car..

Thanks again for any help!

[electricme]

@Bill re Thread INDEX

I'm fine with that Bill, I've got no problems with the change, I wouldn't want you to upset the posts by inserting or removing them.

I will get back to you with this shortly.


@ PowerJunkie

Welcome to the forum.

Your request for help is OK, but no-one here as I know has ever applied the JT to any vehicles electrical system.

Now that said, dosent meen it couldn't be done, just it might not be able to be applied in the way you are trying to do.

If you are looking to attatch it to your engine sensors, then I wouldn't recommend this as at this point of time as no-one here to my knowledge has done it, and I know a slight change in voltage and current with engine management computer could enrich or lean the fuel injection, either one could clog your engine or burn it out, and I would not recommend the JT just for that reason.


But for getting more brake light output, then mabe, but as I mentioned, we have never applied it to this application.
For a start, the vehicles voltage applied to the tail lights would need to be reduced to1 volt max to take advantage of the JT output, then it would have to pass a vehicle inspection by Dept Main Roads, in your country, there would be too many leagal aspects attatched to using the JT this way.
The alternator in the car can put out up to 14.7Volts, so you would need a "regulator" to cope with this.

For instance, the LM317 voltage regulator can reduce 35v down to 1.5volts, but that could still be too high for the JT to cope with.

***EDIT ***
Theres also probably another matter of spikes, the electrical enviroment in a car is "noisy" so the JT would need a fair amount of suppression.

But I like the idea of another way the JT could be used for, full marks for that.



@ The Gadget or IST
Mabe you both or "others" might see a way the JT could be applied in a car?


jim

[gadgetmall]

Thanks to the replies to both of you! I know that I made it right and wound it right since it's lighting up a 3.6V White LED from nearly dead 0.9V AA battery. The issue I'm having is that it's not lighting up when it's connected to a 2V or 2.5V power source in the engine compartment, yet works with a 0.9V AA battery.

The sensor voltage is a constant 2V or 2.5V DC. I'm assuming the sensors provide at least 10 mA since the 2.1V Green LED will light up if I touch the raw leads on to the wires. It lights, but it's a bit dim. Why would you not recommend connecting it to a car engine sensor? The sensors I'm trying to hook up is the Mass Air Flow and Throttle Body sensors. I'll be switching out to dual intakes (which will be including larger Mass Air Flow sensors and Throttle Body senors on each intake) and I'm making this so that I know if the secondary intake is active.

I'm pulling out my hair here since it work beautifully with a nearly-dead battery but not on the car..

Thanks again for any help!

Hi . The "Signal " line you are working with is not designed to feed  voltage and is considered a "Logic " signal . I do not think it will run a Jt as it is Multiplex meaning it carries more than one signal . Chances are that it has logic or clock pulses on it . If you really want to give it a try put a small capacitor across it noting the polarity . It might smooth out the logic in this signal line a bit. and it might not . If not then you will have to use that signal to trigger another circuit with your jtr battery . I know its a little too much over the head but that signal line shows a small amount of Dc and as you can see it barely lights an led which means there is not enuff current in that line to power your current hungry Jt .. Measure the input current of your jt with an amp meter in series with your Jt and you can see how much it needs to work.. BTW you risk Blowing your computer  module messing with those signal lines so please dont blame me  if it blows out  . 

Gadget