Joule Thief

[jeanna]

What bugs me here the most is nobody seems to be concerned with the input consumption. Everyone is rejoiced they can lit two or 300 LEDs, but at what expense?

My AAfuji flash circuit used 1 AA battery for 2 solid hours lighting up a 15watt fluroescent bulb.
The next day after battery recovery it lit the same bulb for 1 hour.
The following day for 30 minutes.
I am sure there was another 30 minutes left in 10 minute spurts.
(That is the reason I pursued the AAA circuit. I isn't cracked yet.)

My apologies for not reporting this.

I think the idea with JT is that you should be able to light LED(s) for a long time,

Actually it is that you can light a led at all. You can light a led on 0.5v and use a battery otherwise considered dead.

The point is if your JT uses 20-25mA of current then you might as well hook the LED directly to the battery source and not bother with anything because you are consuming the actual current LED needs to operate.

I guess you have never tried to do this. Most led's won't light up with less than 1.6volt so you need 3 volts and  resistor. And when you do this it lasts for months. It is hard to remember to keep looking it lasts for so long. I have a white on 2 AAA (triple A) with a 47ohm resistor that is still bright after 3 months. er or was that 4... see what I mean?


Your suggestions are good and practical. I think you will find many on this thread are working toward those very goals.

Thank you for your comments, Amigo,

jeanna

[Mk1]

@amigo

My multimeter must not work well because a got 8 led in parallel fully (thats all the led a got)lit on a brass wire the don't show ac or dc on it , i would need a scope to see but i don't ,really weird .I am having a hard time getting that one.

Not easy to come to conclusions .Impossible ? The metre seems to agree .

7 turns of brass

@ pirate good looking cap!

[amigo]

I guess you have never tried to do this. Most led's won't light up with less than 1.6volt so you need 3 volts and  resistor. And when you do this it lasts for months. It is hard to remember to keep looking it lasts for so long. I have a white on 2 AAA (triple A) with a 47ohm resistor that is still bright after 3 months. er or was that 4... see what I mean?

Hi jeanna,

Actually I did try, long long time ago.

That was my point behind the posting of those two eBooks. One talks about LEDs, what they are, how they are made, the physical and electrical characteristics.

Because LEDs are different it is important to look at their spec. sheets before using them. Red, green, white, they are all made from different materials and have different semiconductor characteristics that need to be taken into consideration when designing a power driving circuit, which brings us to the other book I posted.

I do not know if/how much other people here read books but I would hope that I can spark some interest in pursuing the written word to go along with the experimentation. Someone has already done the fundamental research for us, we just need to apply it to get best possible results.

Thanks.

[electricme]

@ jeanna and others,
Hope this explains how the "bridge" diodes work.

I pulled a plugpak apart, (glue still carnt wiithstand slight hammer plows).
It specs as follows = Primary     240v AC
                            = Secondary  12v AC
Actual output        = 11.2v AC
See 0262.jpg

Next I soldered yellow wires to where the AC connects to the Bridge Diode
Next I soldered the other ends of the yellow wires to the free ends of the Secondary
Next I connect the multimeter to the RED  (+) Positave, and BLACK (-) Negative wires.
Next I select DC range

Turn on power, the multimeter says there is 9.82v DC

Next I solder in a 16v 3300uF Electrolytic Capacitor (acts as a filter and smooths the ripples out of the DC)
and I see the output has climed to 15.30v DC

See 0264.jpg

OK that was a cheep and nasty power supply, no fancy regulator or filtering or voltage selection.
It was made just to show you how to connect it up and what it does.

BTW be careful when soldering in capacitors, put them in the right way, RED wire (+) connects to capacitor (+)
Black wire (-) connects to NEG of capacitor.
LOOK on the SIDE of the capacitor, there should be a STRIPE from top to bottom, this denotes the NEGATIVE connection.

Going to try something new, dont know if it will work until I try it....

jim

[electricme]

@all
dont know what happened here no pictures, I'll try again