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electronic tubes

astrofossilbee

Jul 4, 2022
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Hi,
I have a very neat photo electric effect demo that uses an RCA electronic tube and lasers. I get a little less that 30 micro amps with the violet laser. Does anyone know what photo tube would produce more amps on the micro amp meter? Thank you,
 

astrofossilbee

Jul 4, 2022
2
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Jul 4, 2022
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Yes, photo tubes. Thank you for the reference, but it is way beyond me. I am looking for a photo tube that will register more on my micro amp meter than my RCA electronic tube. Someone I know uses the Sylvania 1P39, but he could not say if his tube would produce more. I use the tube for my photo electric effect. Unlike most P.E.E. sold with science companies, this one actually produces electricity. Thank you
 

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hevans1944

Hop - AC8NS
Jun 21, 2012
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Perhaps it would help us to help you if you would describe what you are trying to DO.

Years ago, when I was still a teenaged electronics enthusiast with no formal training, just "book learning" in electronics, I acquired a small stash of vacuum photodiodes used in 16mm film sound projectors. I had no idea how these little gems worked, but I hooked them up to a variable dc supply that produced several hundred volts and began to "play" with them. I had no datasheets (see the link that @bertus posted above) but was able to eventually get some sort of response from my RCA Vacuum Tube Voltmeter when I shined a flashlight on the photodiode. I was so ignorant at the time that I thought the curved, concave, metal plate visible inside the tube was the anode, and that the thin wire in front of it was the cathode. It wasn't until years later, after I found a datasheet, that I realized my mistake.

This little vacuum photodiode was my first experience with a commercial product that could detect visible light. I knew that "photoelectric eyes" existed because many of the supermarkets in Dayton, OH used them to open doors for customers. Of course those were all eventually replaced with Passive Infra-
Red (PIR) people detectors, but in the early 1960s electronics was in a huge state of flux. It was an exciting time.


Hi,
I have a very neat photo electric effect demo that uses an RCA electronic tube and lasers. I get a little less that 30 micro amps with the violet laser. Does anyone know what photo tube would produce more amps on the micro amp meter? Thank you,
Most phototubes produce very little photoelectric current. The amount of current produced depends on the wavelength of light, the area of the photosensitive surface exposed to that light, and composition of the alkaline metal photocathode. Because of the photonic nature of light, it is possible to observe individual photoelectrons emitted by single photon events. If the light source is of very low intensity, these photoelectric electrons can be multiplied in a photomultiplier tube to increase the measured current to several microamperes. This is more than enough current to amplify and apply to a high-speed electronics counter. Note that the use of a violet laser does not improve the sensitivity of your apparatus. And the optics required to collimate your violet laser become orders of magnitude more expensive than ordinary optics used with a red (632.8nm) helium-neon laser.
 

bertus

Moderator
Nov 8, 2019
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Hello,

Is there a type number on the box or tube?
That way we can see what the specifications are.

From page 93 of the posted PDF (page 91 in the book), the specifications of the tubes are shown.

Bertus
 
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