Light LED with 4 nanoamps / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Light LED with 4 nanoamps

first previous 5 6 7 8 next last

Move Thread

LAN_403

Antonio

Wed Jul 30 2014, 12:35AM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

I will see if I have a suitable inductor. A possible problem with a large inductor is that the spark must be active for longer time, with smaller current, during the time taken by the discharge of the 1 nF capacitor through the inductor. The time is proportional to the square root of the inductance, and the current to the inverse of the square root, approximately. This may cause an unstable spark, wasting energy. In the simulation, with 430 uH the spark lasts for 1.2 us, reaching 720 mA. With 1 H it must last for 50 us, reaching just 16 mA.

Tony Matt

Wed Jul 30 2014, 03:15AM

Registered Member #3700 Joined: Sat Feb 19 2011, 12:59PM
Location:
Posts: 107

Hi !

I undestand that the spark gap requires a good current to hold the conduction ( holdind current). If the current is low, the spark turns off. A experiment with Antonio gap may help find out this issue.

If the spark gap can not deal with so small current, the Zamboni pendulum has to providing the switching. The spark gap time on also may be require to be bigger, in this case the pendulum ( with some additional inertia) will increase the on time.

Other option is a manual switching.

Based on the actual dimensions of the 430uH inductor, a 0.5H inductor with same dimensions will require 34 x more turns, or 1700 turns. A old transformador used in the 5Y3 Vacuun Tube ( 350 - 0 - 350V ) without its stell core may have similar inductance.

Or a just wind a 600 turns coil with a ferrit core from a tv flyback .

Anyway, the results achieved so far are amazing !

Cheers

Antonio

Sun Aug 03 2014, 12:09AM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

I made some tests with larger inductors, with 30 mH, 0.45 H, and 5.5 H, all with ferrite cores and small. The LEDs continue to light up approximately in the same way (the energy of the discharges does not change) but the spark becomes unstable, stretching approximately as the simple simulation predicts, but splitting into a series of sparks, clearly separated with the two largest inductors. The gap voltage appears to be reduced by the large inductors, as the flash rate increases, but there is so much interference from the sparks that it's difficult to make precise measurements. I am not sure if my inductors were not damaged by the 500 V discharges. The result with the original 430 uH inductor, that supports high voltage, was more consistent with the simulation, with quite clean waveforms.
Another video, with the 430 uH inductor and the improved buck converter, showing the capacitive divider used to observe the spark gap breakdown voltage:

Newton Brawn

Mon Aug 04 2014, 03:13AM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

Hi Antonio,

Thank you so much for the simulation showing the results with several inductors and the clarification for my doubts.
I also agree that tha energy in the end of converter is to be maintained despite the inductor size.

Well, I hope Zamboni can show us his aparatus flashing the LED or the neon bulbs ...

Newton Brawn

Sun Apr 12 2015, 04:23AM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

Hi Zamboni !

We would like hear from you if you have done some work with the pendulum and lights !

Regards

Newton

Zamboni

Sun Apr 12 2015, 11:58PM

Registered Member #2836 Joined: Fri Apr 30 2010, 01:24PM
Location:
Posts: 41

I tried to replicate the designs that were suggested, but I was unable to make them work. Some of them required parts that I did not have.

I did have marginal success with taking the 4 nanoamp pulse that is delivered by the Swinger, and channeling it through an LED. I used a larger LED and had a better result. Part of the difficulty is it is just a 4 nanoamp "pulse", there is never a constant voltage.

I should have been clearer about the pulsed, rather than constant, nature of the voltage.

Some of the ideas that were suggested depended on a switch that would contact 2 poles at the same time. That never happens with my device.

I have enclosed 3 pictures that show the only success that I have had. The one called "overview", shows the entire Device. The one called CloseUp shows the clip leads hooked up to the LED.

As the Swinger rotates, the 4 nanoamps of current is delivered to Ground, but only as a pulse. not continuous voltage. I clipped in the LED between the ground terminal, and the batteries negative pole. That does give a barely discernible pulse each time the Swinger makes contact and delivers it's few hundred million electrons (I think that is accurate for 4 nanoamps) to the ground terminal.

These batteries are not able to connect in any way that creates a "short". About the only thing that can be hooked up directly to the battery is a capacitor. Anything else creates a direct short and that is a bad thing. I have hooked the Pos and Neg to a capacitor and it will charge it up to 1700 volts with no harm at all.

I tried hooking up a capacitor between the LED and the negative terminal. It did charge the cap, but there was no way to "switch" the cap on to discharge into the LED.

The very creative ideas that were suggested were wonderful, but I could not incorporate them into the Device. I bet any of them would have worked if I could have devised a way to make them "fit".

Frankly, my understanding of some of the ideas was so incomplete that I was not able to incorporate them. The people on this site are so well versed in electronics that a layman, like myself, can have a hard time following the train of thought.

I tried to get a picture of the tiny flash from the LED, but the camera would not show it. It is just too dim.

I wonder if having a bank of 10 large LED's and have the pulse fire all of them at once would work? I may have to try that. That may create a large enough flash to be picked up by the camera. If I do, I will certainly post a picture.

I really appreciated all the great suggestions.

Paul

mister_rf

Mon Apr 13 2015, 03:21PM

Registered Member #4465 Joined: Wed Apr 18 2012, 08:37AM
Location: Bucharest, Romania
Posts: 145

Nice work. May I suggest you to use some high-efficiency LEDs for your experiments?

I have built a test circuit, controllable current source, connected to some various high efficient LEDs and cranked the dial down to observe the minimum threshold I could see the LEDs light.
It was as low as 10 nanoamps recorded by the camera, but in practice, in a complete dark room the light is quite visible with the naked eye down to 5 nanoamps.
I have been home-testing the following LEDs:

WURTH ELEKTRONIK 151053GS03000 green, 10.000 mcd, 522nm
KINGBRIGHT L-2523QBC-D X-BRIGHT blue, 2.300 mcd , 465nm
AVAGO TECHNOLOGIES HLMP-EG1A-Z10DD red 21.000 mcd 630nm
OPTOSUPPLY OSW54L5111P white 75.000 mcd
CREE C503B-RAN-CY0B0AA1 red 23.500 mcd, 630nm

Zamboni

Mon Apr 13 2015, 06:26PM

Registered Member #2836 Joined: Fri Apr 30 2010, 01:24PM
Location:
Posts: 41

Wow! Thank you for the suggestion. I will buy a few of the models that you mentioned and see which one works the best.

Thank you for all the effort.

I will post the results of my experiments.

Paul

Ash Small

Mon Apr 13 2015, 08:07PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

A string of LED's across the capacitor will only 'fire' when the forward voltage of the string of diodes is reached (I think)

From memory, the forward voltage of most LED's is around 3 volts. A string of, say ten LED's will 'fire' when the capacitor voltage reaches ~30 volts. By choosing a capacitor of the 'correct' value, you should be able to vary the coulombs stored in the capacitor. Youi may require a resistor/inductor to limit the current to whatever gives a visible flash, as the capacitor discharges through the resistor/inductor and LED string (I think, maybe someone can confirm this, and fill in any gaps. I'm no expert in this field, but I think this basic idea, with tweaking, should work. Not sure how often it will fire, though, that depends on current produced and values of components used.)

Can anyone see any flaws in my reasoning?

EDIT: You quite possibly won't need a resistor/inductor to limit current, as most LED's are good for more than 20mA of continuous current, and can take pulse much higher for very short periods.

EDIT: Leakage 'could' be an issue, I'm not sure.

Sigurthr

Mon Apr 13 2015, 11:31PM

Registered Member #4463 Joined: Wed Apr 18 2012, 08:08AM
Location: MI's Upper Peninsula
Posts: 597

You'll get incredible leakage over a range below the Vf. It (any diode) isn't a perfect switch unfortunately.

first previous 5 6 7 8 next last

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob