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I visited a place called ESL Surplus in Mansfield today. They had bought out a big portion of a place in Dayton called Medelson's, and these devices were in that purchase. I remember getting some of these years before at Mendelson's, so it was kind of neat to find more.

These are some sort of unmarked light sensor. Unlike a CDS cell which requires external power (they're just a resistor,) these are actually a little photovoltaic cell inside of the plastic bubble. In bright light, they output about 0.5V. I have no idea who made them or when they were made, save they remind me of devices from the 1970s.

ESL had a bunch of other things from various manufacturer's inventory lines, including old Radio Shack parts. It's not that far so I'll probably be making more trips there in the future.

I visited a place called ESL Surplus in Mansfield today. They had bought out a big portion of a place in Dayton called Medelson's, and these devices were in that purchase. I remember getting some of these years before at Mendelson's, so it was kind of neat to find more. These are some sort of unmarked light sensor. Unlike a CDS cell which requires external power (they're just a resistor,) these are actually a little photovoltaic cell inside of the plastic bubble. In bright light, they output about 0.5V. I have no idea who made them or when they were made, save they remind me of devices from the 1970s. ESL had a bunch of other things from various manufacturer's inventory lines, including old Radio Shack parts. It's not that far so I'll probably be making more trips there in the future.

(post is archived)

[–] • 1 pt

LEDs can work as photovoltaic cells. However, those voltages are just too small to be useful. However, I wouldn't wonder if those light sensors were made in a manner similar to LEDs, and would actually emit some light if you put some voltage through them.

BTW, I've made a little circuit that uses an ordinary LED as a light sensor. Which I think is neat.

[–] • 0 pt

Interesting. I think these are actually little silicon cells, but I’ll try your theory.

[–] • 1 pt

great! Let me know if my theory holds any water.

[–] • 0 pt

If I have time, I'll play a little this weekend.

[–] • 1 pt

I've something similar to these, but they were photodiodes instead of photovoltaic cells. Technically a photodiode is a photovoltaic cell due to the Photoelectric Effect and photovoltaic cells are also diodes because they are P-N junctions so we're both correct on the matter. These are cool finds and it would be nice to see them used in a modern project.

[–] • 1 pt

i have some ideas, so they may end up in something. Other than that, they're an interesting piece, and I don't know that I've seen them elsewhere.

They had a whole box of these things, probably well over 1000 pieces. I'll probably go back and pick up 100 or so.