Lasersaber strikes again. A joule thief king ?

[conradelektro]

I made a Joule Ringer with my big coil and a BC547C transistor which needs very little power (4.4 Volt at 2 mA --> ~0.01 Watt) to light up a 220V 0.7W LED lamp fairly bright. I could not find any good use for the third winding, so it is not connected to anything.

The LED lamp can be connected to the positive rail as indicated in the attached drawing, but one can as well connect it to the negative rail. I did not see any difference in power consumption or LED lamp brightness. (I guess that the BC547C should not be driven with 12 Volt. The aim is a 1 to 1.5 Volt circuit, but this will need thinner wire and more turns for the windings eventually.)

This is nothing new, just some low power Joule Ringer. But next week I will dismantle this coil and wind it again with the same wire and the same number of turns but with two copper strips as I indicated in my post above http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg401739/#msg401739

This should then show whether the copper strips change anything in an interesting way. I will lead out a wire from each of the two copper strips to be able to connect them in several ways to the windings. The first copper strip will be on the core, below the first winding (which is driven by the transistor). The second copper strip will be over the second winding (which drives the LED lamp and is connected to the base of the transistor).

I will omit the third winding at first (it can be added later, but might not fit on the core together with the copper strips, needs thinner wire).

If the copper strips are good for something they should help in any oscillator circuit. But this unfounded guess work might be wrong.

Greetings, Conrad

[SkyWatcher123]

Hi conrad, thanks for sharing your tests.
I tried your latest circuit, which is similar to joule ringer it seems, though could not get it to oscillate with the led bulb i have and also tried christmas led string.
Tried 2n3055 and tip42.
Maybe not enough turns or inductance on my higher turn coil or the ferrite core/coil in general.
I do notice one thing, if i go above 4 volts or so with the other setup, using the third winding to get it to oscillate, it does not make the bulb any brighter.
At that .01 watt input, when you say fairly bright, how bright is that compare to mains powered do you think?
Look forward to your copper strip tests.
peace love light

[conradelektro]

I tried your latest circuit, which is similar to joule ringer it seems, though could not get it to oscillate with the led bulb i have and also tried christmas led string.   Tried 2n3055 and tip42.
Maybe not enough turns or inductance on my higher turn coil or the ferrite core/coil in general.

I could always make a Joule Ringer ring by putting a 10K to 100K resistor between the base of the transistor and positive rail.

One can not put a LED (or a series of LEDs) instead of the "LED lamp" or CFL in a Joule Ringer, because the LED would block the positive half of the sine wave from the coil reaching the base of the transistor (to switch it).

I do notice one thing, if i go above 4 volts or so with the other setup, using the third winding to get it to oscillate, it does not make the bulb any brighter.

I found that a Joule Ringer has a rather narrow range of useful supply Voltage. The necessary supply Voltage depends of course on the windings and should not vary by more than a few Volts. In principle the Joule Ringer will work within a wide supply Voltage range, but only a small range makes it work in an optimal and efficient way. The Joule Ringer I showed in my last post works best between 3.5 and 6 Volt. More than 6 Volt works but the LED lamp does not become much brighter (although the power draw becomes substantially higher), as you noticed as well.

At that .01 watt input, when you say fairly bright, how bright is that compare to mains powered do you think?
Look forward to your copper strip tests.

The brightness of the LED lamp or CFL in a Joule Ringer is overestimated by many experimenters. If it uses less than nominal Wattage the brightness is of course less than nominal. In the 0.01 Watt range my LED lamp shines only with ~10% of the nominal brightness or even less. At nominal brightness (with 0.7 Watt at 220V mains) the LEDs in my LED lamp a piercingly bright.

At 6 V and 25 mA (~0.15 Watt) my LED lamp still does not have nominal brightness, maybe 30%.

Some people did measurements with a lumen-meter and were surprised how little the light output really was.

I like the term "nicely bright", which means that one has the impression that the lamp is "visibly on" in daylight.

But the dimmer light may still be useful as an emergency light, as a flash light or as a night light which many children like to have in the bed room. The eye is very sensitive to pick up dim light (which then looks much brighter than it is objectively).

But be careful, many Joule Ringers make a piercing sound (5 KHz to 20 KHz) which children (and also pets) hear very well. One can avoid the sound by gluing everything on the coil together with a thick layer of glue.

I prefer air core coils (which need 10 times more windings and are rather big), but the circuit then swings at around 80 KHz which nobody hears.

I wonder what copper strips would do on an air core coil? One more test to do.

Greetings, Conrad

[SkyWatcher123]

Hi conrad, thanks for the information.
I took a gutted 6 watt cree led bulb and with proper polarity,
it worked fine with the joule ringer type circuit you showed.
Funny you should mention air coil, as that is what I'm building right now,
waiting for large coil bobbin glue to dry.
Used large cardboard tape roll, 3" diameter and i cut the height
down to 1.5" and have some 1/4" thick, high density fiberboard
disks i had cut from another project for the end pieces.
It will be using the brooks coil ratios.
Going to wind 24awg. bifilar magnet wire and try and get the coil
diameter as close to 6" diameter as possible or when i run out of magnet wire.
After seeing how well tom ferkos is powering non-modified 7 watt led bulbs,
with his satellite air coil motor, though he stops the motor and it self
oscillates as i have seen myself.
Will try standard joule thief and his circuit, which looks like school girl
motor circuit and try some other circuits to see which works best.
He can power six, 7 watt led bulbs to very good brightness on
22 watts, .94 amps-24 volt input.
Though for now, i'm only looking to power one 6 watt led bulb,
so we will see how it works.
Here is a circuit he posted.

peace love light

[NickZ]

  I've had no problems lighting led, CFL, or incandescent bulb using the Joule Ringer circuit. A single transistor, ferrite core, and 12v battery as the power source. The problem has been with the overheating of the transistor, as well as the ringing noise. But, if the voltage is only about 10 volts, the transistor heating is minimal, and the ringing noise can be quieted down by the use of magnetite magnets.
  Here are a few pics of some of my Joule Ringer circuits: