My new project MUhaAHAahaHa!!!

I kinda slipped out of my laser hobby for a while till i was at the bookstore the other day where i saw this book...

in the book there was a guide for building a co2 laser, well a power supply with a pump but anyway...

i bought a 20W tube off of the bay for about 300 bucks and now im gathering parts for the power supply. if anyone wants a copy of the plans pm me and ill get off my bum and scan them for you.

i heard you can use a neon sign transformer to power a laser tube, im gonna look into that till i get the PSU built.

more info to come!!

sounds cool - post pictures as you go!!!

Hammer --

You are undertaking a fun project.  I've got a 15 watt coming plus a 5" FL ZnSe focusing lens.  Basic poly carb safety glasses are reported suitable for goggles.

The neon sign xfmr is a good start with a variac for current control.  I don't know what you plan for AC to DC power but you will probably need about 0.5 mfd filtering - a guess.  
Good Project !!

Mike

Hammer_time - nice project....but you stole my "Daffy Duck Evil Laugh", darnit ! ;D

Keep us posted - between you, and Mike building these, I cannot wait to see the final products !

*sigh* I GUESS It's okay to use my laugh..."it's MINE ! All MINE !"

Sorry - a tad bit of a fan of the Duck....hahahaha

How do you hook up a co2 tube useing a neon sign transformer? or can i use a CPU power supply? i would LOVE to have a 20W laser for 300 bucks but im not too electronic savy...

sonystyle said:

How do you hook up a co2 tube useing a neon sign transformer? or can i use a CPU power supply? i would LOVE to have a 20W laser for 300 bucks but im not too electronic savy...

Click to expand...

Hemlock Mike is your man for the electronics knowledge

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10 POSTS!

Hello,

I got my CO2 tube, and i need some way to hook it up useing a neon sign transformer. Im going nuts just looking at this thing, I NEED POWER!

What do I need to hook it up to a neon sign transformer?

Pics!!! FINALLY!

Sony --

My CO2 tube - 18" long is rated for ~12,000 Volts DC and water cooling. The neon sign transformer will need output around 12,000 volts AC at maybe 20 mA. The ad in the bay should have said what's needed.
A variac (variable transformer) will control current. Watch out on the sign transformer -- They have strange grounds on the HV winding. You may have to isolate the transformer. HV diodes for that voltage may be available on the bay along with caps.
I'm not sure how well the tube will run on AC. That might be a possability for a short test.
Anyhow -- Use spark plug WIRE to handle the volts and BE CAREFUL !!!

Mike

A trip to your local neon/electric sign shop may net you cheap used transformers and some high tension "gto" wire (you don't really have to use "special" HV wire, any wire will do as long as you keep it well spaced away from other components). Shops sometimes sell the used transformers for a few tens of dollars. Try to get the older ones that are not ground-fault protected.

Neon transformers are internally current limited. A 30mA transformer typically runs at 24-26mA, with the rating on the label being a "short-circuit" rating, that is, if you run a wire from one HV terminal to the other, that's the rated current you will get (because of the current limiting, shorting this type of transformer does not hurt it, btw).

Neon transformers of 7500V and up are invariably of the "midpoint ground" type. These have two separate HV coils connected in series inside the case, with the ground connection between them, and the coils operate 180 degrees out of phase with respect to each other to get the rated voltage. This means that both HV terminals are "hot", each providing half of the total voltage, one swinging positive as the other goes negative, etc.

The laser will probably operate on the unrectified AC output of the transformer, with the beam power modulating at 120Hz, but it would be wise to use a full-wave bridge rectifier - laser tubes are typically set up to run on DC, with a large cathode and a small anode. The cathode takes most of the "hit" from the discharge and accordingly is made larger. If you run the tube on AC, both the anode and cathode will share the power dissipation equally, and the anode is likely not designed to do that for very long.