Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [uv]

Ultraviolet electromagnetic radiation, which has a shorter wavelength than visible light. Use for questions about ultraviolet radiation in the context of electronics design, such as the use of ultraviolet emitting LEDs, erasure of EPROM using ultraviolet, etc.

Ultraviolet electromagnetic radiation, which has a shorter wavelength than visible light. Use for questions about ultraviolet radiation in the context of electronics design, such as the use of ultraviolet emitting LEDs, erasure of EPROM using ultraviolet, etc.

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Are UV LEDs really dangerous?

I just bought some UV LEDs I bought them for testing banknotes and identity papers. I read the documentation and saw some warnings about UV light in which the vendor advises not to look directly at the light and not to expose skin to the light. Can…
Superdrac
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6x UV-leds in parallel turning on and off when they should be on all the time

I have 6x UV-leds in parallel driven by a 6V source. The problem I have is that they glow for a little while, then they are completely off for a little while, then glows and then they are off completely. They all do this simulatneously. My…
rzetterberg
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Solar UV index radiation sensor?

I need to measure solar Ultra Violet radiation index. Is there any light sensor that would allow me to do this using an Arduino?
marianov
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LED intensity changes with time

I want to operate a UV LED at continuous 20mA for one week. However, when I measure the LED intensity with a photodiode (see image), I find that the light intensity changes continuously in time. I would like to ask you how I can reduce the light…
Andrea
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Ultra-fast driver circuit for low-power LED

The goal is to drive a low power LED at a very high frequency, with pulses of ~10-100ns width in order to produce a very narrow burst of light. The pulses do not need to be closely packed together, for instance a 1Hz square signal with a very small…
lobis
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Can an EPROM be "refreshed" without UV erasing?

I have lots of AM27C512 EPROMS (with the UV window) which are quite old (1980's.) Using a Xeltek SuperPro 3000U, most can still be read and verified. A few have failed outright and were replaced. Question: Can these be successfully "refreshed" by…
rdtsc
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Determining the best UV exposure time

I would like to manufacture DIY PCB. I am planning to make a UV box like on this link, then I wonder how I can determine the best UV exposure time? or if I use the Sun as the UV source, how I can determine the exposure time as the strength of sun…
Angs
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Ultraviolet sensor response curve

I did a search on "ultraviolet sensors" in this forum, and came up with only three results, so, it appears, that this has not been asked before. I have a hand-held ultraviolet light sensor from Extech (Extech UV505) to measure power density from a…
runcyclexcski
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UV light masking and LCD screens

Not sure if this is the right stack to ask this question on, but it relates to an engineering project that I and a student electrical engineer are starting. Can an LCD screen be used as a masking layer between a UV light and a photosensitive…
Garret Gang
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Is it possible that my UV LED is emitting white light? If so, how would I filter out the white light?

I recently purchased a 365 nm UV LED, and set up the proper circuit. When I turn the power on, the LED lights up very dimly. Is this white light (that's the color I saw) being emitted from the LED? If so, are there any methods (preferably…
ArKi
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Dot Matrix IC message board

I'm trying to make a dot matrix message board -type thing work, The dot matrix IC's are the DL-57 Alpha Numeric Dot Matrix Display [Data Sheet] : https://drive.google.com/file/d/0B6Pibr6_2jwcQ2xmRUIwTjFBZ0k/edit?usp=sharing Which is pretty simple as…
Tropical_Peach
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Coin cell to power a 5mm UV LED?

I am a beginner with LED lights, but would like to use a 5mm UV LED to make a pendant with a small fluorescent crystal. (This is what I purchased…
Devika Menon
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Good high-lumen LED suppliers?

I'm looking for some bright LEDs (in the range of 30-50 lumens, which I think means 2-3 W) for use in a piece of scientific equipment. Can anyone recommend an LED manufacturer that has not just powerful LEDs, but also particularly complete…
pingswept
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How determine the number of LEDs that I need?

So I am trying to do some calculations for a UV curing system that the place I am interning for is working on. One of the tasks that I am assigned to is to determine how many LED does the system need given the energy needed to cure 1 cm square of UV…
S Nguyen
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signs of complete PCB photo-resist development

Currently. I'm making a PCB using the photolithographic method (print on transparency, expose with UV which works, then develop under a bright red LED as the only light source), but half the time, the developing stage is not perfect. I find this out…
user116345
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