Science Buddies: "Ask an Expert"

On the 'Future of LEDs' project, the experiment's list of supplies includes a light to voltage converter (TSL14S). There are only 2 companies that list the part, one is out of stock, the other has a minimum order of 500! They do have a part TSL12S that would fit. Will this work? Will any other components need to be changed to get an accurate result?

Welcome to the forums! I didn't find the "future of LEDs" project, so I'm not sure what you're doing with the 14LS, but I did find a comparison / data sheet of the 12S / 13S and 14S devices. They have different amplifiers, so the output voltage vs. input light are quite different. The 12S maximum output voltage is for 16 uW/c2, the 13S is at 62 uW/c2, and the 14S is 240 uW/c2. These are quite different values, so it may really confuse your data.

BTW, Mouser says their lead time is 2 weeks: http://www.mouser.com/Search/Refine.asp ... -TSL14S-LF

Keith

Assuming you are attempting project: https://www.sciencebuddies.org/science- ... ?from=Home, the Texas Advanced Optical Solutions makes several 640 nm photodiode amplifiers.

The TSL14S / TSL14S-LF parts are 16 mv/(uW/cm/cm) which are less sensitive than the other parts, see: http://www.taosinc.com/productfamily.aspx?sel=ltv

You can make use of the more sensitive parts by utilizing a simple optical filter (aka a pin hole) just like the iris in your eye or the aperture iris in a camera lens. You just need to figure out how to put the detector into something that is light tight and what size hole you need to put into it compared to the size of the detector element to reduce the effective square centimeters of the detector to that of the TSL14S.

In the case of a TSL12S, it is 15.5 times more responsive than the TSL14S, so you need to cover up most of the sensor and only expose about 1/16 th of its active region.

Thank you Mr. Craig and Mr. Keith. I think the only difference between the 14s-lf and the 14s is that the LF is Lead free. I will see if that one is available.