While cleaning up some old stuff in my garage, I just found this thing, that I assume is some kind of sensor:

enter image description here

I probably fetched it on some equipment, but that was probably a very long time ago, I have absolutely no idea where I found that.

It has three pins. It is about 8 cm long, without pins (~3 inch for you guys over there). The label says:

MPLS., MINN. 55422
113228 115030 

(looks like a Minnesota address to me...?)

  • What kind of sensor is this?
  • Does it have any value?
  • Do I need special care to dispose of?

1 Answer 1


It looks like an ultraviolet sensing tube for a flame detector:


They're a couple hundred dollars new but given how critical the application is, I'm not sure you'll have any luck selling it. I'm not seeing anything in the manual about taking special care with handling or disposing of the sensing tube so you're probably good there.

  • 1
    \$\begingroup\$ Thanks. Any idea on what physical law it is based on? How is it supposed to be wired? Just curiosity... \$\endgroup\$
    – kebs
    Feb 17, 2022 at 19:04

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