I dont suppose that you could use a black NTC for a basic power measuring device could you? Are thermopiles temerature based only or do they sense wavelength?
I dont suppose that you could use a black NTC for a basic power measuring device could you? Are thermopiles temerature based only or do they sense wavelength?
Here's an interesting little gadget: A thermal power meter based on a meat thermometer! (Ok, it's a bit more accurate than a meat thermometer, but still...)
Have a look at these pics in the gallery that I just uploaded. It's a power meter that was sent to me by mistake. (Was supposed to go to some dude with a large CO2 laser, but the labels got mixed up and it ended up on my doorstep.)
It's a pretty cool idea, though it's only really practical for larger lasers. (You need to be able to generate enough heat to warm up the sensor block.)
I took some pictures of the thing before I sent it on to the rightful owner. I thought you guys might find it interesting...
Adam
So laser power meters are nothing more than temperature measurement devices with several settings to compensate for different wavelengths?
The lasercheck doesn't measure temperature. It doesn't rely on the light heating something up, but measures the light directly.
With what kind of medium: silicon, cadmium. ..?
I don't know for sure. It wont be CdS. Probably a Silicon or Gallium photodiode.
OK, has anybody analyzed their lasercheks? What's in that window???
I just checked the Coherent website. They say it's Silicon.
The broadband thermal probes work by sensing a change in temperature, yes. Though the really good ones use a TEC rather than just a thermometer.
Smaller power meters like the lasercheck (or the light detector on an Ion laser) use photoresistors like pixpop mentioned.
Adam