Questions tagged [light]

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

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67 views

LED indicators intensity standards

I am trying to find any resources on the LED parameters (i.e. preferred intensity and luminosity ranges) that are used as indicators in various home appliances, such as Networked devices (i.e. routers)...
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1answer
55 views

Turning old floor fan into floor floor study light

I have turned a cheap floor fan into a floor study lamp; i.e. 30cm of 240V 5W a/c LED (under cupboard) strip light facing down on to the desk. These LED strip lights can be easily daisy chained in ...
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Trying to seal light from LEDs on PCB

I have a PCB I'm currently working on in Altium where the only thing on the bottom are some LEDs that I'd like to mount through a cutout on a sheet of plastic, with all of the other components on the ...
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2answers
91 views

Theoretical question: Could an incandescent light bulb be used as a temperature sensor?

Let's assume a plain old incandescent light bulb. It runs on a fixed (assuming an ideal supply grid) voltage and will regulate the current going through it as its resistance raises with the ...
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How to power a 17W T5 Germicidal UVC Lamp?

I recently bought a SBL 350T Germicidal Lamp from American Ultraviolet, but have been having some trouble finding out how to power the lamp since I do not have much experience in lighting and the base ...
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2answers
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Burn hazard of IR LED Array Question

I am performing eye safety calculations on a device and I have hit a roadblock. To perform the calculations I have been following the IEC 62471 "Photobiological safety of lamps and lamp systems&...
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44 views

Should the LED be on the lens side of a light pipe, or the other way?

The image below is from a Bivar cutsheet. I'm trying to figure out which end the led should be on.
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What is this IC “30=N26” in Philips hue garden light

I'm hoping to identify the IC in this Philips Hue garden light controller, in order to replace it. Suggestions on how to identify what it is, would be greatly appreciated.
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1answer
157 views

Why does this part of an OLED filter light only when orientated correctly?

Note: The screen is an OLED screen. I had assumed it was LCD, therefore the post mentions it as such. I was disassembling a Samsung phone (GT-I9305) and was able to seperate the LCD into two sections....
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Do I need the old earth connector when replacing GU5.3 bulb fitting with GU10

I'm switching out a GU5.3 bulb fitting including the transformer with the newer GU10 fitting that no longer needs the transformer. On the old GU5.3 fitting there was a metal connector attached to a ...
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1answer
45 views

12V lighted rocker switch getting hot even without load

Is it normal that 12v lighted rocker switches get hot even when the load is not connected? Attached is the schematic and the PCB layout for such switch: https://lcsc.com/product-detail/Rocker-...
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1answer
76 views

How an animation is done with LEDs?

while(true) {   movePlayer('upright', '10 * Time.deltaTime'); } Here, an animation is done. No button or mouse click is done. Everything moves automatically. How ...
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2answers
106 views

Can light damage a monitor/screen

I was reading some posts about how light can damage a camera by heating it up its internal components? Link: Can camera sensors be damaged by light? If I shine a 150-lumen flashlight at a monitor or ...
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2answers
411 views

How do I drive a 5W low-pressure mercury UVC bulb?

How do I determine the voltage and necessary power supply for this bulb? This bulb is a UVC low-pressure mercury vapor bulb used in my air purifier. It fits in a G23 Socket; normally I would expect a ...
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2answers
50 views

How turn off lights automatically?

I am trying to make system where I want lights to turn off automatically. It should work like that if someone kept lights on by mistake then it should turn off automatically without any human ...
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6answers
2k views

How do I calculate resistance when I have the voltage drop?

This is my circuit: 3 volts in with a 1k ohm resistor in series with the LDR. I have the voltage drop across the LDR but I need to find the resistance.
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1answer
48 views

Problem with new bicycle front led light and old bulb back light

I had a problem with my front bulb light at my bicycle. So, I bought a new one (LED) for the front, but somehow, the back bulb does not work anymore. I have checked the wires for loose connection, so ...
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3answers
138 views

Are these UV-C tubes meant to be run only on pure AC ballast?

I’ve this portable small T5 4W UV-A 300-400nm black light tube lamp with me. I’m trying to see if it’s possible to use a 4W UV-C lamp in the same fixture. But I noticed that the lamp has the violet ...
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43 views

How did an LED go from being a point source of light to an extended source?

A night light with an LED under a dome screen projected a sharp image initially, but a blurry image after the first night. The screen appeared to be undamaged, this led me to believe that the LED ...
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1answer
55 views

Am I thinking about this correctly regarding 12V, 24V and 120V LED lighting?

Most of the LED light strips I see are either 12V or 24V, which require a driver to step down the power from 120v at the wall (thus the little black transformers that come with them). However... I ...
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2answers
86 views

Connecting a light to a battery

my son and I are working through this book called The Thomas Edison Book of Easy and Incredible Experiments. We are stuck on the first experiment where you make a switch to connect a battery to a ...
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1answer
31 views

Dim a 110 Light using 5v PWM with no ZC

I was wondering if anyone has any ideas of a way I could Dim a 110v Halogen light with the use of 5V PWM, or with 0-24v control. My controller, has the basic (designed) 0-24v control. It also has ...
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Is this neon light display real or fake? how does it work? [closed]

Is this neon light display real or fake? if real, then how does it work? https://www.youtube.com/watch?v=xlcywgEMuGI
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1answer
123 views

Can I modify this LED Light Circuit board to not strobe and just stay lit? [closed]

I'm looking for anyone who might know if I can modify this small LED light circuit board to not strobe? I want to use it for my van as indicator lights, I've only managed to find these that will fit ...
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1answer
44 views

Understanding CFLs in Electrical Circuits

I wish to have a better understanding of how CFLs work in a electrical circuit like a home. A CFL broke a little towards the top when I touched it. I noticed it light up at the bottom and then made ...
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1answer
98 views

What is this IC “30=70H”?

I'm hoping to identify the IC on this Philips Hue lightstrip controller in order to replace it. The IC blew after a barrel connector head used had it's polarity reversed, so 24V went in the wrong way ...
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1answer
42 views

Issues encountered when adding DC adapter to light powered by battery

I have an LED light bar powered by 6 AA batteries connected in series. There is also an RF control unit to turn the light on/off. The light eats through the batteries rather quickly thus I decided to ...
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2answers
198 views

Fairy lights dimming over time

I have had this cheap set of fairy lights for a few years. Powered by 3xAA batteries. Recently when they are turned on they start bright as they always were then proceed to get dimmer and dimmer ...
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1answer
29 views

How to use a power meter to measure irradiance?

I have got a Zes Zimmer LMG95 power meter and an RS-ID-5 Fraunhofer ISE WPVS reference cell. The LMG95 has got simultaneous voltage and current measurement and can do custom calculations. The WPVS ...
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2answers
94 views

Logic Implementation

I need to implement a circuit but Im having some trouble since Im novice on electronics. I have 4 inputs. A being ON/OFF switch. B is an Inibitor. C is an Emergency and D is not an adequate ocasion. ...
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1answer
127 views

Electrical induction at a distance through coils for an LED night light

I have 3 decorative candle based night lights, and as an enthusiast project I decided to use LEDs instead of candles to modernize them and make them cooler. I don't want to use batteries, and I want ...
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1answer
74 views

Best sensor to measure light intensity in open room

I am working on a project to understand how robot localization is effected by light levels. I am wanting to build a circuit which can be mounted on a small robot near the camera and can determine lux ...
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1answer
291 views
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6answers
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Lumens specs when buying a flashlight/torch. Why maglite has only 680lm but cheap ones have 900,000? [closed]

I am working as a night delivery driver and when its dark and/or rainy it's almost impossible to read many of the house numbers/names I am looking for. I've heard of Maglite and in fact my friend has ...
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2answers
343 views

NVG compatibility LED Lights

For an avionics application I need to make a keypanel which has NVG compatible LED lights behind its keys. I am trying to understand how does the NVG compatibility (Night vision Goggles) relates to ...
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1answer
49 views

Standard time for LED light testing [closed]

What is the exact timing for testing(continuity, electrical parameter, optical parameter, thermal parameter) of LED lamp after manufacturing?
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1answer
613 views

Bypassing a multi function Christmas light string controller

I'm getting annoyed with my light string, it turns on to a random effect out of 8 and all I want is an always on. I managed to find this great website showcasing different controllers and how to ...
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0answers
91 views

Ordinary LED response to nanosecond pulses

Can anybody explain to me the output waveform generated on pins of an ordinary LED when it is exposed to very short light pulses? I can clearly see that there is a precise difference in the length of ...
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2answers
94 views

Is there a way to measure or infer the color of a material from a distance (~2m), without using visible light?

I've recently started working on a graphics/SLAM project. We've encountered a problem that requires us to measure or infer the color / spectral reflectance (and ideally albedo) of points on objects in ...
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1answer
27 views

Create circuit with triggered light and simultaneous output to computer [closed]

I'm doing an experiment and will be collecting voltage data (from strain gauges) which will be inputted to a computer through a conditioning system. I would also like to collect video footage of the ...
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0answers
26 views

LCD for SLA 3D Printer Resin Curing

I'm doing some research on what types of LCD displays can be used to filter and pass UV light for resin curing - specifically in the context of building a DIY 3D SLA printer. The community commonly ...
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5answers
4k views

Omnidirectional LED, is it possible? [closed]

I have a project in mind that involves lights from a small LED (SMD would be nice) and i've come across this big problem but apparently there's no solution for it on Internet. I need that LED to be ...
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3answers
230 views

How to monitor switch state?

Background I am building a simple web application using raspberry as a server. I am using this raspberry also to control an arduino. A user can send commands through the browser to the raspberry, and ...
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1answer
73 views

Circuit topology name and function for PNP transistor in light barrier circuit

I have seen this rather simple circuit for end position detection of a DC motor drive mechanism. An infrared LED (V402) and a phototransistor (V401) are used as a light barrier. Can someone give me a ...
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1answer
151 views

Help with wiring OEM LED turn signals that has 2 voltage inputs

The term AFS is used in the 2nd diagram to help differentiate between the bulb type turn signals vs the led type. I'm trying to swap my headlights(without-AFS) to a higher trim version(AFS) on my ...
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1answer
115 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 ...
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1answer
101 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
458 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 ...
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2answers
220 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
168 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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