LASER Power Supply


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If you have ever worked with lasers, you know how fun and interesting it can be, you also know how expensive it can be. The high voltage power supplies for the laser tubes are often more expensive then the tubes themselves. This supply can be built with commmon parts, most of which you probably already have in your junk box. The secret is the transformer used. It is a common 9V 1A unit, connected backwards for step up.

Please note that some people may have trouble with this supply. This is due to the slight difference in transformers. For more information on LASER power supplies, take a look at Sam Goldwasser's Laser Supply Info Page.

DANGER: HIGH VOLTAGE CAUTION:LASER RADIATION DANGER: HIGH VOLTAGE CAUTION:LASER RADIATION

Schematic

This is the schematic of the laser power supply

Parts

Part
Total Qty.
Description
Substitutions
R1110 Ohm 10W Or Greater Resistor
R21Ballast Resistor, See "Notes"
D1, D2, D331N4007 Silicon Diode
C1, C2, C330.1 uF 2000V Capacitor
T119V 1A Transformer
S11115V 2A SPST Switch
MISC1Case, Wire, Binding Posts (for output), Line Cord

Notes

  1. T1 is an ordinary 9V 1A transformer connected backwards for step up.
  2. R1 MUST be installed on a LARGE heatsink. A good heatsink is the metal case the supply is built in.
  3. R2 Protects the laser tube from excess current. It should be soldered directly to the anode terminal on the tube. To find R2, start with a 500K 10W resistor and work down until the tube lights and remains stable.
  4. If you have trouble with the tube not starting easily, use a longer anode lead that is wrapped around the tube.
  5. Depending on the transformer you use, the circuit may or may not work. I cannot guarantee the operation of this circuit. Build at your own risk. Some transformers contain very few secondary windings which will quickly saturate the core and basically act like a direct short. The more secondary windings (that is, primary in this circuit) the better.

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Comments

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barath
LASER Power Supply
Thursday, October 28, 2010 10:21:27 AM
i did your transformer inverse thing , the primary shorted out and blew my mains out !!!!

(Editor's notes: Use a series inductor to limit current. )

Hafeez
LASER Power Supply
Monday, February 23, 2009 2:22:04 AM
sir, this is a good project. actually i am a laser sub engineer in paksitan and want to work practically on lasers.
Pawpamayer
LASER Power Supply
Tuesday, November 18, 2008 12:07:37 PM
phamducduy The 9 volt side of the Transformer is connected to the 115 volt line thus causing the stepup effect
Techineer
LASER Power Supply
Saturday, October 25, 2008 1:40:41 AM
While theoretically this should work, the main concern I have is that the transformer primary winding (being used as the secondary) is designed for 120V AC and the insulation materials in the windings and the core may not be sufficient to withstand the interwinding voltages and electric fields produced by peak voltages up to 2250 volts. (120V x 120/9 x 1.414) I would expect to hear some sizzle and possibly see smoke coming from the transformer. Depending on how the transformer is mounted, you might also see arcing to the frame. Use with caution and don't touch the transformer when operating!
Old Guy (retired EE)
LASER Power Supply
Wednesday, October 01, 2008 3:37:37 PM
The one answerer, who said there would be only 9 volts on the output, appears to have missed that the transformer is reversed, so it is a 13:1 step-up, rather than step-down. If we could drop the entire voltage across the input coil (which would normally be a 9v. winding) we would get 115 x 13 = 1495 volts. The problem with this circuit is that too much current flowing through that input coil will burn it out immediately. While this will depend entirely on the transformer selected (that is, the impedance of that coil, which in an AC circuit acts like resistance in a DC circuit) I do not believe a ten-ohm series resistance is sufficient here. If the coil impedance is very low, most of the voltage drop is across the resistor, leaving a lower effective voltage across the coil, and thus the output will be significantly lower as well. (The resistor can take it if it is high enough wattage and well sinked.) As you raise the impedance of the coil to achieve a higher output voltage, you also raise the voltage drop across this very low-current coil in order to give a higher output voltage, you increase the wattage that the transformer must sink to keep from burning up. Overall, this CAN work if you are very selective of the parts used, but anyone building it also has a very good chance smoking the whole project. You might be able to improve the performance but placing a small capacitor in series in the input, but I would do the whole thing differently in the first place. Thanks. Anyone who needs help can contact me thru email and I will try to help your individual needs.
Pawpamayer
LASER Power Supply
Thursday, June 26, 2008 7:53:18 PM
I have a Melles Griot 65 mw laser tube. The box says its Melles # HR551-64 size 15 1/16 X 1 3/4 pwr out 8mw Beam Divergence 2.50mRAD power required 1.7 - 2.45 KVDC @ 6.5ma And I'm looking to build a power Supply for it Any sugestions?
mike lynn
LASER Power Supply (OTHER)
Monday, January 28, 2008 9:14:56 PM
what kind of lasers are used for the power supply.
revannath
LASER Power Supply
Monday, January 07, 2008 3:45:28 AM
sir, this is very good project thank you.
anonymous
LASER Power Supply
Thursday, December 27, 2007 9:11:46 AM
thanks very much
anonymous
LASER Power Supply
Monday, December 17, 2007 3:11:01 AM
Looks like people are running off-tangent with a lot of twisted theory! The Circuit CAN work , pretty well!! James Martin: Dont go by assumptions. Current is Drawn by the load. dont think you know the Laser, but it is 2mW!! Even if the O/p current is 1mA, you can see that the I/P current is fairly small. Some thing like 1W , without the relevant electronic calc. anonymous: Learn physics first, along with good English. The 1N4007 is rated for 1KV max. 3 in series will stand the o/p voltage of 3KV. since the output is 1500V, the diodes have a good chance of surviving the RMS values. ( or even the peak value). Guys : Please stop commenting about anything, without some serious homework!
anonymous
LASER Power Supply
Friday, November 23, 2007 1:27:37 PM
bullshit. Test your schematics before publishing.

(Editor's notes: Tested and verified with a 2mW HeNe tube.)

phamducduy
LASER Power Supply
Thursday, November 15, 2007 8:29:15 AM
I don't understand how this circuit can load R(load) with 1500V ?? We have only 9V in the output !!!
Abel Teklu
LASER Power Supply
Friday, November 02, 2007 7:41:14 AM
It's great. I like it. I want to try it at my university lab. How are the output wave forms? I mean does the circuit make a fine dc output? How much is the ripple factor. And can you send me the answers for James Martin's and Sandeep's questions that are posted on you website? Thank you!Keep it up!boy
SANDEEP
LASER Power Supply
Sunday, September 30, 2007 2:55:10 AM
Sir, this a very nice topic but i can't understand whole thing can you send me the whole project report on my yahoo id I always thankful to your great honour
anonymous
LASER Power Supply
Thursday, September 27, 2007 1:09:33 AM
provide a perfect circuit which will help to find a perfct laser power supply
a hobbyist
LASER Power Supply
Friday, August 03, 2007 2:30:01 AM
it is great but can you elaborate what kind of tube is it?
James Martin
LASER Power Supply
Sunday, July 15, 2007 8:26:43 AM
Yeah, this is okay I guess. From a basic electical stand point it shouldn't really work. For example, we're using a 10 ohm 10W resistor (R1) on the primary. When the transformer is active we're giving it 115V AC (peak). Assuming the coil has a resistance of say 50 ohms, thats 115 x (115 / 60) = 221 W. so R1 would be better suited with a 300W industrial wire resistor rather than a 10W job, and hence the large heat sinking requirements mentioned. The other thing that makes its funtional capacity seem dubious is the specification for a 9V 1A transformer. Theres no ratios inferred so I'm going to guess its about 12:1 if the V out is 1500 from 115. Probably THE most important detail of the plan, but its been left out. And then we're back to that power issue again. 9V 1A infers a 9W transformer that we're about to pump 221W (peak) into. Its probably a fairly ineffective power transformer as well, since its being fed AC voltage, stepping it up, and then jamming the unrectified output into some happless diodes which are going to shave off the negative portion of the voltage (and probably melt anyway because the AC power will be too great on the negative part of the transformer output, causing a cascade melting PN junctions in the silicon, not to mention the positive edge of the cycle will probably melt them anyway. BTW: Why are there three in a row. The only reason you might want to do this is if you want to waste (0.7 * 3) volts. Putting three there does not make them somehow tougher than one. sorry, got a bit carried away there, but as I said, probably shouldn't work.
raul
LASER Power Supply
Tuesday, July 10, 2007 10:37:48 AM
Dear Sir, Using this power supply i will have to connect it with my transmitter/reciever circuit to make it run right?
anthony selvakumar
theory of invertor
Thursday, May 24, 2007 9:42:24 AM
dear sir we are urgently need for theory of invertor and convertor kindly to send our email thanks
shawaiz
LASER Power Supply
Tuesday, May 22, 2007 5:09:13 PM
sir i ask u a question that what is the purpose of laser in this supply.
Danilo Tannymous
UPS 230V 1500VA 1000W schematic diagram
Tuesday, May 22, 2007 2:46:23 AM
Pls. send me a copy of UPS 230V 1500VA 1000w schematic diagram and parts list thanks

(Editor's notes: Good luck on that.)

anonymous
LASER Power Supply
Monday, May 21, 2007 6:55:09 PM
what is most commonly a maximum switching speed for a 1800vdc 5ma laser power supply??? please help
Dima
LASER Power Supply
Wednesday, May 02, 2007 7:40:13 AM
Very interesting progect. But I want to know were can i find a laser tube, plz send me Dima. Russia
ali
LASER Power Supply
Saturday, April 28, 2007 2:48:16 AM
very G O O D but were can i find a laser tube plz send me
Japa and Alcione
LASER Power Supply
Friday, April 13, 2007 8:38:50 AM
ok! OK! Good Job guy This project is very very interessant. my brother and me wish congratulations to you. By Japa and Cyd Blumenau Brazil
anonymous
LASER Power Supply
Wednesday, April 11, 2007 6:50:11 AM
I MEAN TO SAY THAT TRY TO OVERCOME TO DEVELOP A LASER PWER SUPPLY USE SOME IR, OR UR i.e INFRA OR ULTRA VIOLET RAYS ALI ZIA ELECTRONICS ENGINEER.
J.L. Laser
LASER Power Supply
Friday, March 23, 2007 2:34:18 PM
Very good power supply, do you have electronic schematics for a power supply for laser chorus
mani
LASER Power Supply
Tuesday, March 13, 2007 3:59:29 AM
for laser power supply fail by how much ways? give reply. we use in gas only to generate laser
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