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My driver is up and running. It uses a Tiny10 and a buck-converter circuit comprising of a coil, diode and fet. To drive it I use a bootstrapped opto as I have a bag of em and they have nice push/pull setup. By reading ambient and cold side as well as a user adjustable input I can regulate to...

You are absolutely right, they do exist. Technically though, they do not have a side-wall on the copper pads side. That is the bare interconnects of the PN junctions that are exposed. They are usually small tabs of copper or similar. You are right though that they are not electrically...

Yes. All TEC's have ceramic walls as part of the core structure around the PN-junctions. The copper comes ontop of that and is mostly used as heat-spreader and protection as the ceramic is brittle against point-contact and uneven pressure.

Has anyone used a scope to check what the voltage and current-outputs actually look like on these drivers? As long as they have a coil in there they should be able to work correctly, but the pwm frequency is what concerns me.

Depending on the distance to focus point I see my red focuses over a quite long range. The further away the "longer" the area of focus is. At 3" it's atleast 1/3" long with well focused spot. (And burning right through a 1mm gray plastic housing at 192mA.) I was just hoping to add a bit of oomph...

Good point Benm. The difference in red, green, blue is usually not that big a deal but that covers the range 400-750 nm. 830nm really isn't that far out is it? Red and IR are further apart though with 650/830 vs red and green at 532/650.

On a DVD-RW it can't be that weak? After all, it reads and writes both DVD's and CD-R(W).

Can one run both LD's in a dual-wavelength can in paralell for more burning power in a laser-engraver? I am thinking mostly of the IR/RED combos you find in some DVD-burners. Strapping one to my cnc I find it cuts the plastic sheets I need almost perfectly, but a tiny bit more power would be...

For diodes without photodiode I use my dmm to find the right polarity, but I use the diode-tester mode. I know my meter is limited to 3v and 2mA. The meter is a cheap UNI-T UT33D. It is actually limited to the same values in resistance-mode too, but then it does, as Bluefan mention, use a cap to...

alan I would only put inductance in the drivercircuit if I wanted to convert the voltage that way instead of dropping it over the transistor as heat. Inductance in a lm317 based regulator will cause overshoot. In fact, caps on the output of a lm317 reg will cause overshoot too, and excessive...

Sorry Kmor2004 you are absolutely right. I am the one misunderstanding. I did not account for C1 as there was no value on it. I assumed it was small. Ofcource when you use the PWM abd R/C filter to form a DAC you are correct that it will be able to linearly control the transistor although it...

If the driver has a cap in it, it should act against the sense resistor smoothing the voltage over it. However it may not do anything to smooth the current through the diode. Basically, it is only possible to convert voltage by two means: inductance and charge-pumping. A LED won't mind, but a...

The problem is that will operate any diode in pulsed mode. Adding a inductor and diode in there will make it a proper buck converter and they can be nice and smooth. It would help to use a P-FET for highside and a N-FET to pull it's voltage down. That will allow you to run higher v inputs...

Can't even buy ferric chloride here. It's considered a toxic and harmfull substance. Btw, I hope you dispose of those sponges safely as some experienced them combusting or causing other stuff in garbage to do so.

I use UV transfer with philips daylight-bulbs (perfectly safe but 15 min exposures needed) and I etch with sodium persulfate which is safe and doesn't create nasty fumes. It's also clear allowing you to see what's going on. (Turns crystal-blue when used.) I use a side-mounted magnetic stirrer...

I should be etching it already but I can't stop fiddling with it. I decided to make it one-sided for now and by moving some stuff around I got a much better high-current path. The noise created on the supply shouldn't be a problem for the regulator but we'll see. Atleast now it's much better on...

Fiddled with it some more. I recalculated and it is safe to use the 12v bootstrap the way I do. FET gate will never see more than the pump voltage of 12v. That means it's ok to supply it with 15-16v too. So 6-16v supply :) I also adjusted the layout a bit using through-hole headers to get all...

As for the opto: I like optos. Also, this opto is cheaper than a cheap fet-driver and it has push/pull which allows much better switching. Also the isolation it provides helps to avoid getting capacitive pulses from the switching through the gate of the fet and into the microcontroller. I do a...

FEMM was written for magnetics but has since gotten other modes as well. (Like thermal flow.) Finite Element Method Magnetics: Transient Heat Flow Example

My personal favorite is actually jst connectors on wires. I get em from hongkong: JST Cables (10-Pair) - Free Shipping - DealExtreme I use the header-symbol regardless though, and just solder the wires to the pads. Makes for nice boxes. I equip all my Aixis modules with a male jst so I can swap...