Recent content by Mikos

Re: Which thermopile (TEC) is better for power met It should be carbon-based paint (with high concentration of carbon particles). Maybe it would be better if you make it yourself from activated charcoal powder. There are great instructions...

Re: Which thermopile (TEC) is better for power met This would IMHO get you worse results than without it (especially worse reaction time). Thermopiles should have same output independent from which thermocouple in thermopile is heated (if you aim laser on center or on the edge, output should...

Re: Which thermopile (TEC) is better for power met Great! ;-) I am going to buy TEC and electronic parts for thermopile amplifier next week. Just remember that you must attach other side of peltier to some big heatsink (to get accurate readings). Also you must paint it black with active...

Re: Which thermopile (TEC) is better for power met It depends on specific heat capacity and mass of the target. These TECs are extremely sensitive. It even register heat from your body if you put palm of your hand near them.

I want to improve my idea on laser power meter. My first idea has been thermistor in combination with power resistor (see my previous topic). It works, but thermistor has pretty slow reaction time (it takes more than minute to stabilise) and also is too small (I didn't find any big thermistors)...

Re: Very simple DIY laser power meter with thermis I thought that proffesional thermopile laser power meters have much better accuracy in this range. Ok, you are right, then I assume I will have greater error. But still I think that it would be enough for approximate estimation. I will try it...

Re: Very simple DIY laser power meter with thermis I don't think it will be useless. And it will definitely give me absolute readings, not percentage. First I measure power dissipated by resistor. It is U^2 / R (and R is constant, in my case 300 Ohm). The only thing I need is voltmeter. I am...

Re: Professionally looking 200 mW green laser on e Laser has arrived yesterday. It came in sealed antistatic bag and there is label on it: I have tried it with 2 AA Panasonic Digital Xtreme Power (Oxyride) batteries (I can't find Energizer E2 Lithium anywhere, these oxyride batteries should...

It is doable. Five years ago I have build pulse Nd: YAG laser (pumped by gas discharge tubes) with 2 kW peak power (it was school project on Physical week organized by Faculty of Nuclear Sciences and Physical Engineering). With Q-switching (LiF crystal as Q-switch), peak power has been 3 MW...

Re: Very simple DIY laser power meter with thermis I will try it and see if it works. Btw. this power meter should't need calibration (at least in theory) - it is "calibrated" by heat generated with that power resistor (glued to thermistor). But of course there are other factors like unperfect...

Re: Very simple DIY laser power meter with thermis Btw. is there anybody who tried this DIY thermistor-based laser power meter (or "estimator" if you want)?

Re: Very simple DIY laser power meter with thermis Thank you for your offer. But are you sure that shipping costs are only about $2? I am from Czech Republic and I am afraid that shipping costs to/from USA are much greater (about $15 for smaller packages). I will try this DIY laser power...

Re: Very simple DIY laser power meter with thermis Yes, I know that I won't have perfectly absorptive coating, but it should be good enough for my needs. Even if the error will be +- 10 mW (I really doubt that it can give worse error than that in 30 - 200 mW range), it is still acceptable for...

Hello, I will need to measure real output power of fake 200 mW green laser pointer I have ordered on eBay, so I have been searching for some simple and cheap approximate laser power meter. My first idea was simple photodiode + ammeter. I am sure it would work (and it could be even pretty...

Re: Professionally looking 200 mW green laser on e Yes, I have known it isn't Spyder II since the beginning. But I really hope it gives about 100 mW (fingers crossed), if it wouldn't be at least 100 mW, I would try to get my money back and alarm eBay about this scam. Btw. maybe that safety...