This thing is in something similar to a B7G base valve (vacuum tube) but what is it.

 

hi Albert,
Google image search linked.
E
https://www.google.com/search?vsrid...subts=1738250263605&biw=1427&bih=769&hl=en-GB

 

To me it looks like some kind of light sensor. LDR?

 

hi Albert,
Google image search linked.
E
https://www.google.com/search?vsrid...subts=1738250263605&biw=1427&bih=769&hl=en-GB

Link not working for me. Coming back with "Your image didn't match any results."

 

Cadmium sulphide LDR, Type ORP90
http://www.r-type.org/exhib/aaa0627.htm

 

I was going to suggest connecting an ohm meter to which ever pins looked connected on the inside. That device may have been the sensor in a beam-break security system in the early 1950's era.

 

It's a photo sensitive vacuum tube or valve for those across the pond. Commonly called a Photo Tube. During the late 50s and early 60s my dad used them in many of his packaging machine designs. I haven't seen one in many years but that is my guess.
Here is an example which covers how they work.

Ron

 

Oh Wow!! The sensors for the first photo-electric limit switches!!

 

Cadmium sulphide LDR, Type ORP90
http://www.r-type.org/exhib/aaa0627.htm

Yes, exactly that, thanks.
I've never seen one like that.

 

I never had one of those, but I have seen the circuits. I think the rest of the circuit used either a 50L6 tube to drive the relay, and a couple of octal amplifier tubes, and a 35Z5 rectifier or a 117 volt heater tube that I do not recall the type number of.

 

It is reminiscent of the Decatron tubes I worked with many moons ago!

 

That tube looks a little bit like the counter/display tubes I saw in a video that showed the early KRONDECK time counters used for timing drag races a while back. Around 1960, possibly.

 

That tube looks a little bit like the counter/display tubes I saw in a video

That is the use I was referring to in #10 , it counted firing cycles for Thyratron and Ignitron tubes used in welding cycles.
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