High Current Toys for Big Boys

[sbdwag]

Getting ready to build my 5W 808nm C-mount labby and I have amassed several component required for the build. Im basically going to attach a 5v 12a power supply to the diode directly in series with a current sensing resistor and a current limiting resistor. At 7A with about 3V's dumping across the current limit resistor im going to generate about 20 or so watts of power... BIG RESISTOR.

Here are photos and some information that might be of help to anybody thinking about doing this.

This is a Ohmite 50W 1ohm varible power resistor. It is adjustable from .1 to .9 ohms is about four inches long and cost about 15US available from Mouser

Here is a Mean Well 5V 12A switching power supply ready to provide plenty of current to the Diode from Jameco cost 28US About 5.5"x3"x1.5"

These are Ohmite .1 ohm (point one) 1% 10W current sensing resistors availible from Mouser for about 1.60US apiece.

This is a LM338K in a TO-3 Package with heatsink and mounting hardware. With proper sinking and Keeping Vin-Vout less than 10V its possible to get 7.5A's through it. Hook this up to the current limit resistor above using the same pinouts and schematic as a LM317 and youve got a great constant current device but you will need about 7V for it to work. About 12US with sink and hardware from Jameco

Anyway I hope this helps to anyone who is interested in doing a project like this and by all means this is trial and error for me if you have suggestions or a better way please let me know.

Regards
sbdwag
​

 

[lasersbee]

Hey sbdwag....

STOP.... STOP.... STOP...
you're starting to impress me with your research....:gj:

Can't wait to see that one built....:beer:

Jerry

 

[Gryphon]

Thats one monster resistor Keep us posted when you finish it, i can't wait to see it!

 

[Illuminum3415]

I'm on the edge of my chair on this project of yours, it looks impressive thus far XD

Thats one monster resistor Keep us posted when you finish it, i can't wait to see it!

Wirewound power resistors are always impressive at first sight.
Its only of the few passive components that you can use to beat someone to death with if there was that need

if you think 20Ws are impressive, consider a 200W ones

 

[Laser_Ben]

Why are you using this driver? Why not use a FlexMod which can do 8A?

 

[heruursciences]

At some point it is cheaper to make your own, I find that coat hangar wire works wonders when designinmg a ballast for multiple AMP laser diodes.

 

[Cyparagon]

Lawl, it's hardly aesthetically pleasing though. Someone might think you're running an abortion clinic.

 

[moninosis]

Lawl, it's hardly aesthetically pleasing though. Someone might think you're running an abortion clinic.

You could use that for an abortion I'm sure...

 

[Mohrenberg]

On that note, I love dead babies.......

i've got nothing else to say, move along.

 

[VW]

On that note, I love dead babies.......

i've got nothing else to say, move along.

Lol watt?

 

[HIMNL9]

Lol watt?

Uhm, at least 50, i guess .....

 

[moninosis]

5 watts. hahaha. That's wattsup

 

[Helmholtz Watson]

Ha, that's not a resistor it's a heating element!

I like really big capacitors. Used to have a few 1f ones but sold them as I had no real use for other than making enormous sparks since I grew out of extreme car audio.

 

[moninosis]

yeah I used to have this huge 5 farad cap, I got it from an electronics teacher, I think he stole it from a power plant? lol.

 

[Flaminpyro]

on that note I love smell of napalm in the morning......... :crackup:

On that note, I love dead babies.......

i've got nothing else to say, move along.

But any way where did you buy your "C" mount I been trying to get chris to answer my PM's for weeks every once in a while he comes across with ONE PM to ask me the same question ? so where are you getting your "C" mounts at ? as I would like to play with one, maby some 9mm's also....
Thanks !
Pyro...

 

[LuxIgnis]

Hello I bought a 4-6W 915nm and I want to also build my driver. Does your power supply have TTL???