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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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10th Aug 2022, 12:47 pm | #1 |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Light bulb Identification.
Hello,
Just wondering if anyone is able to Identify this old light bulb \i found among my stuff. The only marking I can see are the numbers 403 on the base. Thanks, Jonathan. |
10th Aug 2022, 12:54 pm | #2 |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
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Re: Light bulb Identification.
At first sight I thought it was an old transmitter dummy load but I would say it is a photo cell? John.
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10th Aug 2022, 1:08 pm | #3 |
Nonode
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,152
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Re: Light bulb Identification.
Have you tested it with a series resistor to see if it is a Neon?
What size is it? |
10th Aug 2022, 1:09 pm | #4 | |
Pentode
Join Date: May 2009
Location: Byfield, Northamptonshire UK.
Posts: 112
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Re: Light bulb Identification.
Quote:
Ian E Addendum: See https://www.electricstuff.co.uk/Photocell.html "2nd row, 2nd tube from the left. Last edited by Ian E G7OLT; 10th Aug 2022 at 1:31 pm. |
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10th Aug 2022, 1:17 pm | #5 |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
Hi, thanks.
I haven't performed any testing on it yet. Looking at the construction of photo cells it does look structurally similar. |
10th Aug 2022, 1:19 pm | #6 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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Re: Light bulb Identification.
I also agree that it is a photo cell.
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10th Aug 2022, 1:22 pm | #7 |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
It's about the same size as a domestic incandescent light bulb, and has two wire connections that feed into the side of the base.
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10th Aug 2022, 4:20 pm | #8 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
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Re: Light bulb Identification.
Does it's resistance change depending on how much light falls on it? If so...it works.
Dave |
10th Aug 2022, 5:35 pm | #9 |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
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Re: Light bulb Identification.
It may need an 'exciter' voltage to kick it off. Not sure. John.
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10th Aug 2022, 6:01 pm | #10 |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
I'll do some experimentation later tonight (no innuendo intended).
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10th Aug 2022, 6:24 pm | #11 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,552
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Re: Light bulb Identification.
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10th Aug 2022, 6:45 pm | #12 |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
I managed to sneak off and test this, and indeed resistance does increase in the dark so this is definitely a phototube. I see these were used for "Optical sound" in film projectors among other things.
Would these also have been used in laboratory equipment - spectrometers etc? I also had some photomultipliers in the same storage box. |
10th Aug 2022, 6:53 pm | #13 | ||
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
Quote:
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10th Aug 2022, 6:55 pm | #14 | |
Pentode
Join Date: Feb 2018
Location: Nottingham, Nottinghamshire, UK.
Posts: 225
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Re: Light bulb Identification.
Quote:
Thanks. |
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11th Aug 2022, 3:39 pm | #15 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
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Re: Light bulb Identification.
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