Identifying Missing Valve Info

[Hermit6345]

I have not tried this myself, but it looked to be something which could help in identifying those valves where all the info has been rubbed off. I have a fair few of those. Maybe this is something that everybody except me knows about!!

http://www.youtube.com/watch?v=MBE6j...eature=related


Worth a try anyway.


Ian

[Bertusvz]

Hello,

I think that the amount of UV in the torch is revealing the information.
The "white" leds are made of blueish (with a lot of UV) leds with some stuff inside to have the white shining.

Greetings,
Bertus

[newlite4]

Very interesting, thanks for the link. As he says, there may be some UV emitted by these LEDs.
Neil

[HamishBoxer]

Impressive and will give it a go.

David

Not quite UV but very blue, does the job and is filed in my 'tips and tricks' section of my brain.

[Bertusvz]

Hello,

White leds are made of GaN:

White Light

When light from all parts of the visible spectrum overlap one another, the additive mixture of colors appears white. However, the eye does not require a mixture of all the colors of the spectrum to perceive white light. Primary colors from the upper, middle, and lower parts of the spectrum (red, green, and blue), when combined, appear white. To achieve this combination with LEDs requires a sophisticated electro-optical design to control the blend and diffusion of colors. Variations in LED color and intensity further complicate this process.

Presently it is possible to produce white light with a single LED using a phosphor layer (Yttrium Aluminum Garnet) on the surface of a blue (Gallium Nitride) chip. Although this technology produces various hues, white LEDs may be appropriate to illuminate opaque lenses or backlight legends. However, using colored LEDs to illuminate similarly colored lenses produces better visibility and overall appearance.

This quote is from this page on technical specifications of leds:
http://www.theledlight.com/technical1.html

Greetings,
Bertus

[vinrads]

That is just brilliant i am off to buy myself a l.e.d torch

[davidw]

Well spotted Ian..I'm going to give it a try later.

[John M0GLN]

If it is the UV that's revealing the missing text, then a keyring LED UV torch for checking bank notes might do the trick, you can buy these very cheaply. under £2.00 from some places.

John

[phasedout]

Brilliant i have a led light, same colour will use to identify some of my unmarked valves.....Alan.

[60 oldjohn]

I have tried it, seems to work better on some than others. Some are too far gone to read. John.

[Bertusvz]

Hello 60 oldjohn,

The difference can be due to the different type of paint used.
Some might react better on the UV than others.

Greetings,
Bertus

[Phil G4SPZ]

I tried this tip using an LED head torch, but unfortunately it revealed nothing on a selection of old and more recent valves with missing markings

[oldticktock]

I have a huge box of unknowns and it did not work for me either back to the slow detective work for me.

[Hermit6345]

I tried it on modern valves which would have had the details painted on the side and that did nothing. An older type with the info on the top worked to some extent. I can only surmise that it's the amount of UV in the light source. I don't have a torch like the author of the video. Mine only has 7 leds in it My local shop was out of stock of the 72 led model. As John suggested, those things for testing curreny notes might be better. The author of the video clip wanted feedback, I think I might send him some!


Ian.