Welcome to Laser Pointer Forums! If you are looking for a laser you may want to check out the database of laser pointer companies. The link will open in a new window for your convenience.

 Laser Pointer Forums - Discuss Laser Pointers High voltage generator (20-30 kV) Laser Pointer Company Database     Laser Top Sites List     Lasers by Type     Green Lasers

05-07-2015, 02:00 PM #1
 Class 1 Laser Join Date: Mar 2014 Location: Italy Posts: 50 Rep Power: 7
Jaggions
Class 1 Laser

Join Date: Mar 2014
Location: Italy
Posts: 50
Rep Power: 7
High voltage generator (20-30 kV)

Hi there. I just made a cool high voltage project and I wanted to share it with you.

I took a flyback transformer out of an old CRT television, an electrical ballast and two random plastic film capacitors. I made a little circuit that looks like this (click to enlarge):

The output is of about 20-30 kV at 15 kHz and 10 mA, but I didn't measure the exact voltage, so this is just an estimate.

Photos time! Click to enlarge
Some arcs:

Burning a piece of paper:

That's it! Feel free to post here if you have any suggestion/question.

P. S. The output of this circuit can be lethal under certain circumstances. Don't try to do that if you don't have any experience with high voltages and currents.

__________________

Last edited by Jaggions; 05-07-2015 at 05:45 PM.

05-07-2015, 04:22 PM #2
 Class 4 Laser Join Date: Sep 2007 Location: Wisconsin Posts: 8,852 Rep Power: 1350
Cyparagon
Class 4 Laser

Join Date: Sep 2007
Location: Wisconsin
Posts: 8,852
Rep Power: 1350
Re: High voltage generator (20-30 kV)

How did you select which primary tap to use?

Quote:
 Originally Posted by Jaggions 50-60 mA, but I didn't know how to measure exact voltage and current,
No, not 50-60mA. The arc would be bright white. Your setup is probably in the single digit milliamps, and is therefore not lethal.

Voltage can't be measured with standard equipment unless you rig up a voltage divider with 10s of resistors. Current on the other hand is easy and can be done with any ammeter. The ammeter does not pose a resistive load, so it will not be damaged by the voltage. Simply put your DMM across the secondary to measure short-circuit current (Be sure to have DMM in mA or A mode!). Do not perform this measurement for more than a few seconds though, since the secondary heats up.
__________________
A problem well stated is a problem half solved.

05-07-2015, 04:33 PM #3
 Class 3R Laser Join Date: Jun 2012 Location: Illinois Posts: 2,032 Rep Power: 452
TheDukeAnumber1
Class 3R Laser

Join Date: Jun 2012
Location: Illinois
Posts: 2,032
Rep Power: 452
Re: High voltage generator (20-30 kV)

Quote:
 Originally Posted by Cyparagon No, not 50-60mA. The arc would be bright white. Your setup is probably in the single digit milliamps, and is therefore not lethal.
I'm not sure about that, back in my physics labs we were all told that it only takes 8mA to stop the heart. I know using low power sources it's unlikely the 8mA will make it to the heart, but with what jaggions is playing with I wouldn't go as for to say "therefore non-lethal"
__________________
“Absence of evidence isn't evidence of absence."
http://laserpointerforums.com/donations.htm
“It is impossible that any ill should happen to the man who is beloved of the Lord; the most crushing calamities can only shorten his journey and hasten him to his reward. Ill to him is no ill, but only good in a mysterious form. Losses enrich him, sickness is his medicine, reproach is his honour, death is his gain. No evil in the strict sense of the word can happen to him, for everything is overruled for good. Happy is he who is in such a case. He is secure where others are in peril, he lives where others die.”—Spurgeon
Avatar by Yohsi Yaki

Last edited by TheDukeAnumber1; 05-07-2015 at 06:18 PM. Reason: grammar

05-07-2015, 05:38 PM #4
 Class 1 Laser Join Date: Mar 2014 Location: Italy Posts: 50 Rep Power: 7
Jaggions
Class 1 Laser

Join Date: Mar 2014
Location: Italy
Posts: 50
Rep Power: 7
Re: High voltage generator (20-30 kV)

Quote:
 Originally Posted by Cyparagon How did you select which primary tap to use?
I found the primary by checking the resistance between the pins of the transformer. The correct pins are usually the ones with a 1 ohm resistance between them.

Quote:
 Originally Posted by Cyparagon No, not 50-60mA. The arc would be bright white. Your setup is probably in the single digit milliamps, and is therefore not lethal. Current on the other hand is easy and can be done with any ammeter. The ammeter does not pose a resistive load, so it will not be damaged by the voltage. Simply put your DMM across the secondary to measure short-circuit current (Be sure to have DMM in mA or A mode!). Do not perform this measurement for more than a few seconds though, since the secondary heats up.
You are right. I measured the current this way and it is about 10 mA.

Quote:
 Originally Posted by TheDukeAnumber1 I not sure about that, back in my physics labs we were all told that it only takes 8mA to stop the heart. I know using low power sources it's unlikely the 8mA will make it to the heart, but with what jaggions is playing with I wouldn't go as for to say "therefore non-lethal"
10 mA should not be lethal (unless you have a pacemaker or some sort of heart disease), but it's still very painful. I wouldn't try that on myself.

EDIT: Very high frequency electric current can also cause tissue burning, even if it does not penetrate the body far enough to cause cardiac arrest.
__________________

Last edited by Jaggions; 05-07-2015 at 05:40 PM.

05-07-2015, 07:02 PM #5
 Class 3R Laser Join Date: Jan 2009 Posts: 1,237 Rep Power: 460
DashApple
Class 3R Laser

Join Date: Jan 2009
Posts: 1,237
Rep Power: 460
Re: High voltage generator (20-30 kV)

Nice : )
__________________

Would you leave me here behind
Would you love to watch me cry
Would you like to fly away
I can show you the truth
If you'd only let me loose
If you told me what you need

I'll turn to code
The processor will know
Our digital humanity ......

05-08-2015, 12:04 AM #6
 Class 4 Laser Join Date: Sep 2007 Location: Wisconsin Posts: 8,852 Rep Power: 1350
Cyparagon
Class 4 Laser

Join Date: Sep 2007
Location: Wisconsin
Posts: 8,852
Rep Power: 1350
Re: High voltage generator (20-30 kV)

Quote:
 Originally Posted by TheDukeAnumber1 we were all told that it only takes 8mA to stop the heart.
Yeah, if you've got leads attached directly to the heart maybe. 30mA is generally the low-end of what's considered lethal, and that's in sensitive individuals

You wouldn't want to zap yourself with a flyback, just as you wouldn't want to shoot yourself with a BB gun. Sure, you can argue a BB gun could kill someone, but that doesn't mean a BB gun is considered lethal.
__________________
A problem well stated is a problem half solved.

06-06-2015, 02:47 AM #7
 Junior Member Join Date: Nov 2012 Posts: 26 Rep Power: 0
ilovegm
Junior Member

Join Date: Nov 2012
Posts: 26
Rep Power: 0
Re: High voltage generator (20-30 kV)

I've heard that tv technicians who get zapped are more badly injured due to their hands being flung into the sharp edges inside the enclosure
__________________
Diode lasers are dope! (p & n type)

I prefer red lasers. Darth Vader has one.

0.005W Ghetto supercapacitor laser
0.200W LPC-826 Lab style host
1.000W M-140 C6 host

06-06-2015, 11:09 AM #8
 Super Moderator Join Date: Nov 2008 Location: Liverpool , UK Posts: 4,869 Rep Power: 1156
ped
Super Moderator

Join Date: Nov 2008
Location: Liverpool , UK
Posts: 4,869
Rep Power: 1156
Re: High voltage generator (20-30 kV)

Quote:
 Originally Posted by ilovegm I've heard that tv technicians who get zapped are more badly injured due to their hands being flung into the sharp edges inside the enclosure
Having been on the wrong end of an Anode cap countless times back in the 90's during my time as a TV technician, I can confirm this to be 100% true.

The zap you get is more of a burn, unless you get between the isolated/non isolated side of the chassis at the same time, that'll ruin your day every time.
__________________
@Ped0771

5000mW Coherent/Kenometer

Lazoors:
550mW C6 9mm lens
445nm Blord "Big Boy" 3.36w 9mm lens
445nm Jarob C6 kit (on 3rd diode) 1.9w 9mm lens
Various 532n nm 15mw pens ~ 600mW monster
515nm 34mW Direct Green Diode - LaserBtB
Various 650's - 1mW pens upto 300mW C6's

06-09-2015, 08:49 PM #9
 Class 3B Laser Join Date: Jan 2014 Location: Deployed to Iraq Posts: 4,233 Rep Power: 2068
Class 3B Laser

Join Date: Jan 2014
Location: Deployed to Iraq
Posts: 4,233
Rep Power: 2068
Re: High voltage generator (20-30 kV)

I accidentally got across 2500 VDC capable of 500ma once, that was enough for me.
__________________

http://www.lexellaser.com/techinfo_wavelengths.htm

Laser Safety:
http://www.laserpointersafety.com/index.html

Angular Size Calculator; use with diode angle of radiation specification to calculate the needed lens diameter for a given FL:
http://www.1728.org/angsize.htm

Divergence to spot size calculator: http://tinyurl.com/spotsize - 1 mRad is about .057 degrees which from the earth would expand to be ~10% the diameters of the moon or sun at their distances.

Divergence Calculator: http://www.pseudonomen.com/lasers/ca...alculator.html - Measure your lasers beamwidth at 1 foot & then at a further distance to calculate the divergence.

Online calculator to determine spot intensity at different mRad's & powers @ distances: http://tinyurl.com/divergence-calculator

Laser Power Density Calculator: http://www.ophiropt.com/laser-measur...ity-calculator

How to build a laser beam expander to reduce divergence: http://tinyurl.com/BeamExpander

RHD's Relative Perceived Brightness Calculator. Compare brightness @nm: http://lsrtools.1apps.com/relativebrightness

YAG Power Calculator, i.e. convert ns @ mJ to peak power in watts http://tinyurl.com/YAG-Pulse

The forum costs more to run than donations received, if you wish to help click this link: http://laserpointerforums.com/donations.htm

_______

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

All times are GMT. The time now is 04:14 PM.

 -- DarkShadows V5 -- Responsive LPF -2562016 -- Default Style Contact Us - Laser Pointer Forums - Archive - Top