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Author Topic: Lasersaber strikes again. A joule thief king ?  (Read 412354 times)

TinselKoala

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #165 on: June 03, 2014, 08:16:08 PM »
I've found that the MPSA18 and the BC337-25 are similar but in some circuits one works better and in others, the other one. Lately I build everything with sockets or easy solder pads so I can do easy comparisons without changing much else in a circuit.

d3x0r

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #166 on: June 04, 2014, 07:32:11 AM »
I don't know how many of you are youtube addicts...


https://www.youtube.com/watch?v=s3T6kEic5G0


Not just a glimmer of light.

d3x0r

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #167 on: June 05, 2014, 05:03:14 AM »

I had 2 NTE47's, but ended up overpowering both... so while I was looking for a replacement I noticed some details.


NTE47 Vbe On = 0.7   (100Mhz)  Hfe 400-1150
MPSA18 Vbe On = 0.65 (something) (100Mhz)  Hfe 400-1500


Which is a lower base-emitter voltage drop than anything else I have... many are 1.2+


Germanium transistors (they say) can have a Vbeo  of 0.15V  (fanstastic!)  but the gains on the germanium transistors I see are only 100-200.....




And Germanium transistors have a 'cutoff frequency?'  They are actually really slow like between 2-10Khz ?




conradelektro

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #168 on: June 05, 2014, 02:16:26 PM »
I made some scope shots from the MPSA18 circuit of Lasersaber as depicted here http://laserhacker.com/?p=410

The MPSA18 has a very short on-time (about 600 nS) and this is the reason for the low power draw. My replication draws less than 0.3 µA (but the red LED is very dim).

see also: http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg405172/#msg405172

In Lasersaber's latest video (no circuit drawing available yet) https://www.youtube.com/watch?v=s3T6kEic5G0 the LEDs are much brighter. But as far as I understand the power draw is several hundred µA.

Greetings, Conrad

d3x0r

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #169 on: June 05, 2014, 03:55:02 PM »
I made some scope shots from the MPSA18 circuit of Lasersaber as depicted here http://laserhacker.com/?p=410

The MPSA18 has a very short on-time (about 600 nS) and this is the reason for the low power draw. My replication draws less than 0.3 µA (but the red LED is very dim).

see also: http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg405172/#msg405172

In Lasersaber's latest video (no circuit drawing available yet) https://www.youtube.com/watch?v=s3T6kEic5G0 the LEDs are much brighter. But as far as I understand the power draw is several hundred µA.

Greetings, Conrad


Ya; but before I blew up my NTE47's I had a hand-crank lantern, and attaching it to a 3300uF cap takes only a few turns to charge to 9 volts....


Daniel Nune'z hand crank demonstration...
https://www.youtube.com/watch?v=Z4mTA794U4E  (for instance) I think he's using a similar driver....  no idea how big his cap is...


Oh; but ya  mine only runs for seconds... using the oroiginal lighs from the lantern; which IS longer than they run directly on the generator....

Farmhand

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #170 on: June 05, 2014, 10:00:30 PM »
The brightness of the LED's on video is deceptive. If I look directly at a properly driven 5 mm bright LED it has a temprary blinding effect and a small green dot with a purple circumference remains in my vision for some time.

In my opinion we want to drive the LED's to deliver similar or at least usable light levels efficiently.

The looper "tag" is misleading it gives the impression that the devices are self powering when in fact they are just using a very small power draw to show LED's partially driven, either time wise or power wise as well.

Take the low powered LED "looper" light and read a book by it or look for something in the pitch dark with it.

My garden lights drive the LED's to good brightness, it takes power to do that, all we can hope for is better efficiency, or using less power for less light output.

..

conradelektro

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #171 on: June 05, 2014, 10:19:04 PM »

Ya; but before I blew up my NTE47's I had a hand-crank lantern, and attaching it to a 3300uF cap takes only a few turns to charge to 9 volts....


Daniel Nune'z hand crank demonstration...
https://www.youtube.com/watch?v=Z4mTA794U4E  (for instance) I think he's using a similar driver....  no idea how big his cap is...


Oh; but ya  mine only runs for seconds... using the oroiginal lighs from the lantern; which IS longer than they run directly on the generator....

@d3x0r: I have built a hand cranked generator from a stepper motor http://www.overunity.com/13639/hand-cranked-stepper-motor-as-a-generator/msg365643/#msg365643. And now I know what I can do with it. Together with LaserSaber's latest low power circuit it could be used to charge the cap quickly to get some light.

@Farmhand: you are right that LEDs are incredibly bright when driven with nominal power. But for some applications (like a night light or just a novelty item) glowing LEDs can be nice.

I got some MCP1623T and MCP1640BT voltage regulators (from 0.8 Volt are boosted to 3.3 Volt) and will try a LED driven with a 1.5 AA battery, but the LED will be driven with nominal power (some 30 mA at 3.3 Volt), which should give 6 lumen with the LEDs I have got. The two booster ICs cost less than 50 cent each and need two caps and a 10 µH coil. The efficiency of the booster ICs is 70% to 85% at what I want to do. This is nothing new, but I want to have a hands on comparison of LED brightness with Joule Thief type circuits. I agree that LED brightness is often over estimated by Joule Thief enthusiasts (like myself).

Greetings, Conrad

SkyWatcher123

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #172 on: June 06, 2014, 05:12:25 AM »
Hi folks, Hi conrad, i know what you mean about perception of light output.
Though when using a sensor like that from a solar garden led light, it can be fairly accurate when using an off the shelf, non-modified led bulb.
I built a joule thief, ferrite flyback core with secondary coil (1.65 watt input) that gives around 147 lumens per watt from a non-modified, 6 watt ecosmart led bulb, rated at 450 lumens.
147 lumens per watt, is almost double the stock 75 watts per lumen rating.
Soo, if we apply this to one of these bulbs, http://www.amazon.com/G7-Power-Vintage-3-6-Watt-Replacement/dp/B00GIOXBBM/ref=pd_sim_hi_5?ie=UTF8&refRID=03WSVN1WD4ANP9EZ8RZD
Then at 138 lumens per watt stock output, we can achieve around 276 lumens per watt with the joule thief secondary style setup, maybe.
Will have to buy a bulb to find out, wheres santa, hehe.

peace love light
 ;)

MarkE

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #173 on: June 06, 2014, 12:49:00 PM »
Hi folks, Hi conrad, i know what you mean about perception of light output.
Though when using a sensor like that from a solar garden led light, it can be fairly accurate when using an off the shelf, non-modified led bulb.
I built a joule thief, ferrite flyback core with secondary coil (1.65 watt input) that gives around 147 lumens per watt from a non-modified, 6 watt ecosmart led bulb, rated at 450 lumens.
147 lumens per watt, is almost double the stock 75 watts per lumen rating.
Soo, if we apply this to one of these bulbs, http://www.amazon.com/G7-Power-Vintage-3-6-Watt-Replacement/dp/B00GIOXBBM/ref=pd_sim_hi_5?ie=UTF8&refRID=03WSVN1WD4ANP9EZ8RZD
Then at 138 lumens per watt stock output, we can achieve around 276 lumens per watt with the joule thief secondary style setup, maybe.
Will have to buy a bulb to find out, wheres santa, hehe.

peace love light
 ;)
How did you measure the total light output?  That's not an easy thing to do without specialized equipment. 

SkyWatcher123

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #174 on: June 06, 2014, 05:27:39 PM »
Hi marke, as said, i used a photoresistor from a solar garden led light.
Set meter to kilo-ohms and placed sensor in same spot on non-modified 6 watt-450 lumen ecosmart led bulb.
Stock output from grid power, bulb shows 1.53 kohm on photoresistor.
Using joule thief with secondary coil circuit, shows 2.83 kohm on photoresistor.
That works out to around 54 percent of the grid powered output, which is around 243 lumens or 147 lumens per watt at 1.65 watt input.
The light that is radiated from this lamp is definitely indicative of 243 lumens to my eyes.
It is every bit as bright as a 25 watt incandescent bulb.
peace love light
 ;)



Farmhand

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #176 on: June 07, 2014, 12:09:18 AM »
@d3x0r: I have built a hand cranked generator from a stepper motor http://www.overunity.com/13639/hand-cranked-stepper-motor-as-a-generator/msg365643/#msg365643. And now I know what I can do with it. Together with LaserSaber's latest low power circuit it could be used to charge the cap quickly to get some light.

@Farmhand: you are right that LEDs are incredibly bright when driven with nominal power. But for some applications (like a night light or just a novelty item) glowing LEDs can be nice.

I got some MCP1623T and MCP1640BT voltage regulators (from 0.8 Volt are boosted to 3.3 Volt) and will try a LED driven with a 1.5 AA battery, but the LED will be driven with nominal power (some 30 mA at 3.3 Volt), which should give 6 lumen with the LEDs I have got. The two booster ICs cost less than 50 cent each and need two caps and a 10 µH coil. The efficiency of the booster ICs is 70% to 85% at what I want to do. This is nothing new, but I want to have a hands on comparison of LED brightness with Joule Thief type circuits. I agree that LED brightness is often over estimated by Joule Thief enthusiasts (like myself).

Greetings, Conrad

Yes I have to agree that dimmed LED's are useful as are glowing ones I have some ornaments with glowing LED's myself, also flashing LED's are cool as well especially as indicator lights to tell if something is operating or just to save power and extend run times for nightlights ext.

But we must remember every now and then to re-calibrate our eyes if we don't have appropriate meters, we can do that by blinding ourselves with a single properly driven 5 mm LED, or by doing simple light on the wall comparisons with the properly driven LED.

I have a few things that light the LED properly, one is a fake pistol cigarette lighter with an LED laser sight mock up, it's very bright.

The point I want to make is a competition to see how long we can glow LED's for doesn't really serve any purpose. It's the efficiency of electricity to light that is important.

We can dim LED's by reducing current with uninterrupted DC, or we can reduce the time the LED is on by using pulses, both ways reduce the total light emitted, but the pulsing can keep the LED bright while flashing. Just because the flashing is not visible to our eyes and the flashing is the same "brightness" as the properly driven LED does not mean that the pulsed LED is outputting the same "total amount" of light as the "constantly on" one.

Power input/output is not always related to brightness, but it is related to total light output.

Given the same conversion efficiency for pulsed and continuous DC LED lighting circuits the one with the most power input (staying with design limits) will output the most total light. That's what I think.

.

Brightness and total light output are as different as Power and Energy.

Brightness is the rate of light output. Basically.

..

SkyWatcher123

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #177 on: June 07, 2014, 04:19:22 AM »
Hi folks, well for practical purposes, if a light is not blinking perceptibly and lights up a room just the same as plugged in to the wall, then it fulfills the purpose.
Same as video frame rate, if we can watch the movie just fine without flicker, then it does the job of giving us a fluid video to watch.
As far as more total light being output, doesn't really matter to me, as long as the light can allow humans to see a room and the stuff in it properly.
peace love light
 ;)

Pirate88179

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #178 on: June 07, 2014, 06:53:30 AM »
Hi folks, well for practical purposes, if a light is not blinking perceptibly and lights up a room just the same as plugged in to the wall, then it fulfills the purpose.
Same as video frame rate, if we can watch the movie just fine without flicker, then it does the job of giving us a fluid video to watch.
As far as more total light being output, doesn't really matter to me, as long as the light can allow humans to see a room and the stuff in it properly.
peace love light
 ;)

Well said.

Bill

d3x0r

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Re: Lasersaber strikes again. A joule thief king ?
« Reply #179 on: June 07, 2014, 08:00:34 AM »
I dunno LEDs are peculair things with joule thieves... I found that voltage was cheap to get, it's current that's the limiting factor... but LEDs are good because no matter how many in series you put, they draw the same current... so building up a high voltage to light LEDs in a long chain was really easy and seemed to take less input current than the total multiple of voltage gained... something like OUBrads just posted...


but LEDs in quantites of 1000 begin to get expensive... so if I wanted to build a 1500V joule theif for 20mA output it begins to be very expensive :(