Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

HeNe Laser Power Supply Components

  1. May 22, 2016 #1
    I recently salvaged a Melles-Griot HeNe laser from an FTIR system. I neglected to save any of the electronics except for what I think is the step-up transformer attached to the laser tube. The laser is "05-LSC-708-540" and the transformer is "05-LPM-850-045".

    I have a 12V power supply, but was wondering I need to also come up with additional control electronics, like a current controller, to get the laser to work. There are only two wires going to the transformer (+12V and ground).

    I see at the link below, that I should get a fuse in case things go wrong.

  2. jcsd
  3. May 22, 2016 #2


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    since transformers don't operate with DC voltage, There will be more components needed ...
    an oscillator to convert the 12V DC to AC to feed to the transformer
    The red and black HV+ and - leads out the right side will be most likely in the order of 500 - 1500V DC
    check the datasheet spec's for the tube for a more accurate voltage recommendation
    There will be AC off the secondary of the transformer that, most likely, is rectified by one or more diodes
    to produce the HV DC for the tube

    do some googling for the tubes datasheet, It may even have a recommended power supply schematic included

  4. May 22, 2016 #3
    Sorry, should have mentioned that the foil-wrapped brick attache to the tube also has "Input:12VDC WMAX:9 Hz:N/A Output: 1.10-1.50KVDC 4.5mA" written on it, so it likely has the oscillator and rectifier built in. The beefy wires that I assume are the HV leads are affixed already to the laser tube.

    It does have a small purple wire labeled CDRH that is looped back on itself. From here: http://www.repairfaq.org/sam/laserhps.htm#hpsrtc0

    I think that that purple wire is a turn-on delay.
  5. May 22, 2016 #4

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    How familiar are you with laser safety ?

    That's a 5mw laser so check local regulations to be sure you can legally own one,
    and never point it skyward because you don't know where the airplanes are.. it's a big deal to pilots when a laser beam comes through the windshield.

    Sorry if you're an old hand. but you didn't say.
  6. May 22, 2016 #5
    I'm a physics graduate student in a lab that routinely uses 18W IR lasers, and I bought some cheap ~633nm laser goggles. I know of no regulations prohibiting such a low power laser in my area. I am more unfamiliar with the HV part of the supply, but with the leads going right into the tube, I don't plan on messing with that part.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted