You can also use 10 x10 ohm SMD resistors to calibrate it. At 10V it will give you 1000mW. I calibrated mine this way and the readings are quite accurate. Check out my 400mW lazer review and compare to the power certificate that came with the laser.
Soldered the resistors to an "S" and added some thermal paste at the buttom of them to calibrate my LPM.
Here also some other voltages to compare with:
2,24 Volt - 50 mW
3,16 Volt - 100 mW
4,47 Volt - 200 mW
6,32 Volt - 400 mW
Just make sure your DMM is really very exact in showing the correct voltages.
Soldered the resistors to an "S" and added some thermal paste at the buttom of them to calibrate my LPM.
Here also some other voltages to compare with:
2,24 Volt - 50 mW
3,16 Volt - 100 mW
4,47 Volt - 200 mW
6,32 Volt - 400 mW
Just make sure your DMM is really very exact in showing the correct voltages.