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Questions tagged [light]

Light is a tag about anything generates photons in the visible spectrum

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1answer
41 views

Building Led light which work on 230V supply

I have a couple of 9W LED bulbs(1) at home with blown drivers. I got some replacement boards(3) with driver circuit and LEDs on the board itself. Now that the old LEDs(2) along with the aluminum PCBs ...
9
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0answers
1k views

Can 2 light bulbs of 120V in series be used on 230V AC? [migrated]

I'm considering to buy full spectrum incandescent bulbs in the US, to be used here in Europe. Here these types of bulbs are rare, since it's mostly LED these days. First I thought I needed to step ...
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1answer
55 views

LPC1768 - Green LED when LDR sees light, Red LED when LDR is covered

I have been trying to achieve a task I am working on and I believe I am almost there. It successfully changes colors whenever I cover it but when it does, the red LED keeps blinking instead of it ...
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0answers
32 views

Irradiance sensor circuit

Im trying to measure the irradiance from the sun using the following TIA circuit: I'm using a BPW34 photodiode due to the good spectral range and for being cheap. Also the datasheet provides a ...
8
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1answer
92 views

Which part of some LED TV screens acts as two gratings crossed at non-straight angle?

Some modern LED TVs display the following diffraction pattern (photos taken from this question): In my answer to another question about the origin of this pattern I explained that this should be due ...
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1answer
54 views

How to filter out certain wavelengths of light [closed]

I am trying to filter out certain wavelengths of light and I was wondering if there is a way that you can filter them out. I am using Silicon Photomultipliers (Linked below) and I only want to detect ...
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0answers
66 views

Photodiode to detect light

For a university purpose I am preparing a project, actually I am thinking of using a photodiode in reverse bias in order to measure intensity of light. I divided this project in some phases: 1) ...
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2answers
76 views

Light sensors sensitive enough to detect for PWM from CF and LEDs?

I have an extreme sensitivity to PWM light sources such as computer screens and light bulbs. This can make it very challenging to make a purchase as I end up having to do lots of guesswork with ...
2
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1answer
46 views

LED selection for my application

I need to select LED/LEDs for a light source in my project. The requirement is that the light source should approximately be able to project light beam of 1.5m diameter on a surface, from a distance ...
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0answers
39 views

Light illumination method for video camera and CV detection

My control application implements human face detection and recognition with using of CV library. My device uses usual VGA USB video camera. Problem: Good and uniform light illumination allows ...
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1answer
25 views

Directly Using a Smart Charger with An Old Vector Hunting Spotlight? [closed]

I have an old hunting spotlight (http://documents.dewalt.com/documents/English/Instruction%20Manual/Vector/VEC184POB.pdf) which has a small 12V sealed lead-acid battery. The chargers that come with ...
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0answers
48 views

LED Light changes color on being turned on/off simultaneously

What type of circuitry/driver is present in the lights that change color on being turned on/off ? I have a LED tube light which cycles through 3 modes (i.e. color 1, color 2, both color). Its circuit ...
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1answer
53 views

Is Power Factor only relevant at rated load in Light Equipment?

As you might know, LED lamps over 25W require a minimum 0.9 power factor in Europe. I have designed a PSU for a specific LED lamp which is rated about 50W. There is a PFC-stage (crm) in order to ...
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3answers
82 views

dc voltage control for LED lights?

I'm looking for a little bit of help on a project I'm working on. I need to find some way to make led light bars (18w and 120w) to automatically start out dim and gradually brighten to full ...
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6answers
4k views

Can antennas be viewed as light sources?

Clearly antennas are nothing but a device to radiate the electrical energy through electromagnetic waves. Since visible light is also simply a certain range of frequencies, isn't it more easier to ...
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0answers
89 views

Bare LED light flickering on constant voltage pover supply

I have this LED light which started blinking under some use. So, I desoldered the SMD LED component and hooked it up to a variable power supply. When I apply 6V, the LED starts to emit a little bit of ...
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1answer
59 views

Light bulb LED equivalent of a CFL (Compact Fluorescent Lamp)

If I have a CFL light bulb of 100W what would be (how many watts ) its equivalent in LED. In the place where I live LEDs have taken over and CFLs are no longer available, but I need stron bright ...
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1answer
37 views

Magnetic ballast with g23 bulb with capacitor

I am trying to make a UV-b photo-therapy light and want to make sure I'm understanding the circuitry correctly-so i don't hastily burn a $50 bulb. Im using a Phillips PL-S 9W/01/2P (link here). It's ...
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1answer
62 views

Using an analog voltmeter to display the changes in out put made by a dimmer switch for a light

I'd like to preface by saying k know little to nothing about electrical engineer but would like help with making a lamp. I want to use a volt meter style gauge to display a different reading for a ...
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2answers
67 views

What kind of IC drives this safety LED night light?

This night light LEDs circuit has three 4 positions: off fast blinking slow blinking LEDs always on The big central component is a switch. I was wondering what IC drives the LEDs ? From what I can ...
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3answers
59 views

Non electrical background trying to make a cool little custom project - Help please?

Brief bit of background - I've built my own PC's, I've repaired phones, changed plugs, fit light fittings from diy stores, and have a basic (very basic) understanding of electronics, but have found ...
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2answers
408 views

How can I use an LED driver (QX5252) to light up 3 different color LEDs (Green, Yellow, Purple)?

I am trying to light up 6 LEDs with the common garden light circuit (2v Solar panel and 1.2V battery). The problem is that I want to light up 2 yellow LEDs, 2 green LEDs, and 2 purple LEDs ...
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2answers
491 views

Is the speed of electrical signals always constant within a CPU? [closed]

Microprocessors rely on assumptions about how long it takes for electrical signals to propagate through combinational logic circuits. As far as I understand from reading "Modern processor design", ...
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2answers
93 views

What is the response curve of a CMOS sensor cell to the amount of light?

Using my Nikon D5100, shooting RAW pictures and using Darktable to disable absolutely all contrast curves, white balancing, sharpening and even the debayering, I've measured the average value of the ...
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2answers
70 views

LED light bulbs in low atmospheric pressure

I have these (https://www.amazon.co.uk/gp/product/B01DBOKZVK/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1) LED lightbulbs. Can I use them in a pressure of ~30kPa (21" Hg vacuum)?
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2answers
73 views

Swap between two colors without an additional light?

A Quick Note I'm not sure of a more accurate name for this question. If you can think of a better name, feel free to edit and change the name. Also, I'm not the greatest with technical terminology so ...
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1answer
283 views

Normally On Circuit with Positive Trigger?

Pardon my lack of technical terms here; essentially I have an under glow kit on my car (along with some other lighting) that I want to expand the circuit on. I bought a pair of 5 pin relays to ...
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1answer
94 views

Is it possible to make a lightbulb light up by wetting your hands? [closed]

I was recently watching an Electroboom video on free energy devices, but my question is not about any of that stuff. Here's the video. At about 5:50 he claims and seemingly shows that he can light up ...
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2answers
112 views

Build my own light bulb

Before I start: I do not have a lot of experience in electrical engineering so I would appreciate clear statements and extensive explanations to be able to follow your ideas. I am currently trying to ...
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4answers
366 views

What is the RGB value of Edison Light Bulbs? [closed]

I've been doing a little electrical engineering (outside of my lane a bit). I'm trying to get the RGB values for Edison light bulbs. Can anyone provide me with those?
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4answers
4k views

Why does an LED have to be a diode?

I know LED stands for Light Emitting Diode; but why does this component need to be a diode to emit light? My question assumes that the "leds" we see everywhere (for lighting, screens, etc) are ...
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1answer
116 views

How to connect a LED G13 Tube directly to a power socket?

I am trying to build my own cheap lighting for my greenhouse. I have found a couple LED tubes that would be perfect for the task, only they are supposed to be mounted on a lamp of some sort. They have ...
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1answer
111 views

Light source that withstands extreme conditions [closed]

I am designing an aircraft obstruction light, and Federal Aviation Administration (FAA) requires crazy requirements for their standards. One standard goes as following (From FAA AC 150/5345-43H): 4....
2
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1answer
142 views

Can this 1000W ballast be wired for 240V and plugged to 120V to run a 400W MH Lamp?

I've a 1000W MH ballast. Is it okay to use the wiring for 240V the ballast and use it on 120V? Like does it reduce the ballast to 500W? I've attached a video for better understanding of how the bulb ...
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3answers
332 views

What makes same wattage led light bulb brighter than the other? [closed]

I noticed that one 10 W LED light bulb was 800 lumens and the other 1000. Both were warm white, 4000K, 80 CRI. What exactly makes one brighter than the other?
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2answers
357 views

Can you damage an LCD screen with a camera flash, high-powered flashgun/speedlight?

I'm curious as to what the limitations are in regards to uv radiation on LCD screens when subjecting them to high intensity light sources such as camera flashes (such as a nikon or canon speedlight). ...
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1answer
35 views

Infrared diodes illuminator scope

Can anyone tell me if there are certain specific criteria that states whether an infrared led can be used as an illuminator particularly the ones they use on hunting scopes. Would a tsal6100 for ...
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1answer
103 views

How to determine DC input voltage of a device without its charger? [closed]

Had a MotoMaster (Canadian Tire) 27/3 LED flashlight for 4 years now. Model was discontinued 2-3 years ago. Lost the charger at least 2 years ago and the light's battery FINALLY died today (!!) I ...
3
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1answer
131 views

Manufacturing of Translucent LED Indicating Symbols (e.g. router indicator lights) [closed]

I've been researching how manufacturers create custom LED-illuminated symbols such as those seen on the router in the image below: I haven't been able to find any information online from custom ...
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1answer
38 views

Multiple lights dimming using single TRIAC zero detcetion module

We know well we can dim single lights using single TRIAC module with the help of PWM signals from controller. My question is, I want to control the lights which are placed on hall. Let us consider 15-...
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1answer
237 views

Which one is better to build lux meter, either LDR or photodiode?

I want to add the lux meter to my application. My controller works with 3.3V and ADC max reading voltage is 1.2Vref. I tried with LDR but I'm not able to get accurate values and the values also not ...
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2answers
613 views

Safety of “UV” LED

I am curious as to whether LEDs like these ones http://www.led4everything.com/catalog/product/view/id/410/s/st0028/ are harmful, they are advertised as UV. But are they just purple LEDs or actual UV? ...
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0answers
56 views

LCD panels used in projectors - What are their limitations?

It's important I point out immediately that I am an absolute novice at all this. I am trying to self-teach myself the basics by building things but it is a slow slow process. So please bear with me if ...
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0answers
94 views

concave conical lenses on 5050 SMD LEDs?

Is there any way to put plano-convex conical lenses, or something broadly equivalent, on 5050 SMD LEDs? The lenses I'm talking about are the type commonly built into cheap christmas-tree lights: As ...
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5answers
302 views

Rated vs. actual power usage of a linear fluorescent lamp

After having some power issues, I've decided to investigate the largest power drains in our company, and I've arrived at a realization that 128 lights adds up to a lot of power (and that's not even ...
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1answer
60 views

g23 socket and 11W UV-C bulb

because UV-C machines tend to be expensive, our lab working on biological/biochemical research has reverted to attempting to build a machine from scratch. Therefore, we recently purchased a G23 ...
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1answer
57 views

how to determine value of a power storage capacitor in an intermittent circuit [duplicate]

I made a post earlier about this but apparently there weren't enough details and i didn't explain it well enough so i will try this again: I have a circuit which runs on intervals of 0.75 seconds on/...
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2answers
90 views

Can kitchen salt break a LED lamp circuits/board? (weird problem) [closed]

Hello everyone I have a really weird situation. I had two Yongnuo YN-600 Air LED photo/video lights. On these lamps it says "DC, max input 8V, 5A". I was sold AC adapters to those lamps 12V 5A. They ...
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1answer
2k views

How can I reuse a crowdled bracelet?

I have been to an event last night, where I some wristbands produced by the Crowdled company (see links at the end). Material of one band: 3 colored leds (2 in total) and a button. Runs on battery. ...
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3answers
65 views

Making an automatic night light

I'm a total beginner so I'm sorry for stupid question(s). I want to design a circuit and I'm stuck. Here's the description: Photosensor outputs 0V until the ambient light decreases below certain ...