Slightly OT: Tenma Light Meter vs. MeterMan LM631

[S4MadMan]

Does anyone have any comments on the Tenma Light Meter? How does it compare to the MeterMan? Thanks.

The detailed specs are here:
Please clicky CLICK. :-)

 

[Doug S]

Here is a link to specs for the LM631:
http://www.metermantesttools.com/downloads/manuals/LM631_OP_INST_ENG_a_crop.pdf
I don't own either so I cannot give you any hands-on impressions. I am a bit of a test equipment geek and can offer a comment or two based on the specs only.
1. Note that the accuracy specs apply for only a 2856K CIE standard illuminant. While both specs imply compliance to the CIE photopic response curve, this is a bit of a red herring since they do not specify the accuracy of compliance to the CIE photopic curve so hence the accuracy is not specified for sources with spectra different from the 2856K CIE standard illuminant. A really good laboratory photosensor may have a match to the CIE photopic curve over the entire spectrum to within 2%. Rest assured that neither of these instruments are in that league.
2. The LM631 offers lower ranges which many here would find useful.
3. The LM631 offers an auxilary output which is useful for datalogging. Some folks here have put this to good use for runtime testing.
4. Quite a few folks here have the LM631 and it seems to be a de facto CPF standard. I suspect that you will get some comment on it.

 

[Sigman]

I have the LM631. I've not used it alot, however like the lower ranges for LED readings. I use some of WaveTek's equipment at work and like it, that's one of the reasons I went with the LM (as well as the positive comments I received from some of the talented modders here on the CPF).

20k LUX being the max on the LM...I don't have a need to go over that! As was quoted to me in an email or an earlier post in reference to light meters (do a search)...if you need to go over 20k back up and do the math.

The stated accuracy on the back of my LM package is 3%. The stated accuracy on the link to the Tenma is +/- 5% (+ 2 digits).

Here's a link to Circuit Specialists LM631 They still have the LM on sale for $85 + a free $30 DMM. I think when I bought mine, anything over $50 was free shipping, so it was the best deal for me!