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

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50 views

Led grow light problem

I am making an LED grow light. I have 72 3W LED on heat sinks on an aluminum board wired in series. I have 5 50W constant current LED drivers to power it. I have tried wiring the drivers every way ...
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0answers
36 views

Light sensitive resistor

I have a CdSe light sensitive resistor which goes from 0.1k to 30k light->dark . It works fine outside the circuit. When I pass +/- 1V 400Hz AC across it, it seems to always have a low resistance. Is ...
2
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3answers
46 views

Magnetic reed switch current ratings

I wish to use some 12 V, 5 W xenon light bulbs under separate shelves of a cabinet. I'd like them to power-on using a magnetic reed switch attached to the cabinet door. The magnetic reed switch I ...
2
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3answers
113 views

How do Wi-Fi controlled light switches feed themselves?

There are smart light switches in the market that are Wi-Fi controlled like Plumlife (formerly ube) and Belkin WeMo. I wonder how they control the electricity that they operate on. When I unplug my ...
0
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1answer
58 views

Adding a switch to an existing light

I've read about 3-way and 4-way switches but I don't understand something. I am aiming to create a bluetooth controlled home network. One of the modules would include a light switch. How would I go ...
2
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2answers
64 views

Run 12v Incandescent Bulbs off Fluorescent Ballast

Can I use a 120v AC to 12v AC electronic transformer to power 12v bulbs? I have a 150 watt transformer that I tried connecting to a single 10w incandescent bulb, but the bulb just flickers at a low ...
1
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0answers
27 views

Lighting in the hall: How to substitute a missing wire? [migrated]

I have a problem with the lights in my appartement. The current setup is below (and photos further down): simulate this circuit – Schematic created using CircuitLab There are two ...
1
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3answers
70 views

Lumens vs Watts

What of this words define the intensity of the light of a bulb? Lumens or watts? I don't know if I am right. Lumens means intensity of the light and watts the consumption of the bulb
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1answer
47 views

how to turn backlight on for BC1202A LCD

Hopefully this question isn't too novicelike: I have an LCD (BC1202A) that I want to drive from a parallax propeller board. Spec data:link1 and link2 After hours of mucking around (mis-wiring, ...
1
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2answers
117 views

Two relays for DRL on a car

I am trying to make a circuit for my newly installed DRL (Day running lights), what I am trying to do is have the DRL run all the time, turn off when using high beam, dimmed when headlights are on. I ...
1
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4answers
277 views

Which circuit to use to automatically turn off the backlight of a GLCD after 30s?

Have you ever seen smart phones automatically turn their screens off after a short time to save the power? I want to do it on the back light of my GLCD (ks108sed). Descriptions: Back light will ...
0
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4answers
130 views

Cool White LED bulbs: Are they “full-spectrum”?

I don't have much knowledge on LED lights and find the technology quite fascinating (yes, I know, it is not that knew!) I have read that in order to create "white" light, LEDs actually need to emit ...
0
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0answers
38 views

WeMo Wireless Light Switch US convert to be used in UK?

I am in love with this thing and just cannot believe that it runs 120V 15A. Step down transformer would be too big since this thing should fit into the wall. http://www.belkin.com/us/p/P-F7C030/ ...
0
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1answer
38 views

How to make a dimmer for a 11W CFL?

I have a desk lamp, that uses 11W/827 CFLs (current one is an Osram Dulux S) The lamp uses a power supply ("Type BL1"), but it seems the transformer acts more like an AC/AC power converter, as it ...
0
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1answer
40 views

Using 6x58W fluorescent lamps instead of 6x55W, what could possibly go wrong? [closed]

I'm planning to buy a fluorescent photography lighting head, but the manufacturer specified it uses 6x55W lamps, but I want to use Philips Graphica 58W lamps. 3 watts more per lamp, doesn't look like ...
1
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5answers
157 views

How to generate Red light from a Blue-Dominated Spectrum

I have a white LED light source, the spectrum of which looks as follows --- want to filter out red light from this white LED source. But as you can see the spectrum dwindles in the red zone. And ...
2
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1answer
50 views

Taking power from two different feeds

Probably a silly question I know but I'm not all that good when it comes to wiring but at the same time don't want to blow myself, or my car up! I have a set of sidelights/ daytime lights that take a ...
1
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2answers
59 views

Do parabolic reflectors in globes increase the brightness of the filament's light, or just 'spread' the light?

If you compare a traditional 60W incandescent globe with the same filament specification as one with with a parabolic reflector built into the globe, does the (usually) aluminium reflector actually ...
1
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1answer
59 views

Digital light organ

I am trying to make a circuit that takes an audio signal from an MP3 player and converts the signal into digital signals based on frequency. Audio In is the is the signal from the audio jack of an ...
-2
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2answers
88 views

Is it possible to run 230V LED - or flourecent “spiral-tube” - lightbulb with a 9V battery?

I would like to power a 230V LED lightbulb with a 9V battery. I assume I'll have to dissect it... Surely there must be some sort of power-converter and rectifier from 230V-AC to something a lot ...
0
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1answer
170 views

How to build a blinking 12V indicator LED light

I attempt to build a blinking circuit using 12V truck light ( like this one: http://www.princessauto.com/pal/en/Tail-Lights/4-in-LED-Stop-Turn-Tail-Light/8126047.p). I have try to build a single LED ...
0
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2answers
449 views

What makes an incandescent light bulb run out?

What is or are, the most likely and common ways - the weak links in the chain (including I assume poor electricity wiring / configured housing) - that cause a traditional incandescent light bulb to ...
3
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1answer
163 views

MCU Electronic Power Switch

How would I wire a light-emitting device (not necessarily an LED) in the following schematic to indicate the input (High to run) is high? Would it be in parallel with R4? Before or after R3? ...
0
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1answer
73 views

Connect two-function brake light to three-function car circuit

I need to replace my 12VDC (bulb based) brake lights but I am unable to find a three-function light (Running/Brake/Off) with the same specs. I did however find a two-function light LED fixture ...
3
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1answer
227 views

Most efficient way to power both 12V and 5V off a battery

I'm building a lighting project for Burning Man and I have both 12V inputs and 5V inputs that need to be powered off of batteries. Here are the max loads: ATmega328p - 25mA at 5V Addressable LEDs - ...
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1answer
185 views

How hot does a florescent light filament get?

I understand that a florescent light bulb radiates light as a result of exciting mercury in the bulb with electrons and those electrons are emitted by a filament. What is the highest temperature that ...
1
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1answer
87 views

Rigging an MRI machine with club speakers and lights

I'm using a magnetic resonance imaging (MRI) machine to fMRI trial subjects while they experience club-like conditions. This means I need loud, high-fidelity speakers, flashing multicolored lights ...
5
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2answers
292 views

Why don't solar cells produce visible light when supplied with electricity?

... A cursory Google search didn't reveal an answer... Is the energy conversion a one-way process?
0
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1answer
58 views

CFLs and Incandescent Lightbulbs in household light fixture

I have a few light fixtures around the house where there are multiple sockets per fixture - 4 sockets/fixture in the kitchen, dining room, bathroom ceiling light fixtures. I began the process of ...
0
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1answer
103 views

SMD LED Perimeter Lighting with PWM for Dimming on each colour

simulate this circuit – Schematic created using CircuitLab So from the start what Im trying to achieve is drive way lighting in which each colour is separately dimmable with a pulse width ...
1
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1answer
53 views

LED light muliplexing

Is it possible to multiplex multiple power LED strings from a single driver unit to reduce heat generated? For example I have two 20 Watt (100V @ 200mA) LED lamps. If I include an electronic switch ...
0
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2answers
114 views

Transmitting data over light with USB

I'm working on a project that uses light as a medium for data transmission. I would like to achieve about 2-3 MB/s. It suppose to virtually behave like any LAN cable. I would want to know if it is ...
0
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1answer
47 views

Avalanche Photodiode Current Gain

I'm designing a readout circuit for an APD manifactured by Hamamatsu Photonics (datasheet). However, I've found myself lacking some information about exactly how would the device behave in my ...
0
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1answer
643 views

Is an 120V LED light bulb compatible with a 220V mains? [closed]

Would an excellent LED light bulb like the Cree 60 Watt Replacement TW Series (designed for the US market) work in European countries? On the packaging it says "Use only on 120 volt AC circuits." and ...
4
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2answers
180 views

Are photoresistors reliable for light sensing applications?

I've used photoresistors for hobby projects before, such as this one: http://www.foxytronics.com/learn/electronics/kit-guides/starter-electronics-kit-guide/making-an-led-light-sensor However, now ...
0
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0answers
59 views

Relationship between light intensity, angle of incidence, resistance of LDR

I want to find the mathematical relationship between the resistance of an LDR, its area, light intensity, angle of incidence of sunlight. It would be great if someone can direct me to a place where I ...
0
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2answers
48 views

How to find the value on a chart scaled in decibels

I have the following chart The blue line is the one I am interested in. The question is how can I determine the value in LUX if I have the output voltage? The problem is that I don't have any ...
1
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1answer
87 views

How would you go about creating a lux meter for very low light (0.0001 to 1 lux)?

I like to take pictures of the the sky in really dark places like Death Valley. To get an estimate of exposure times for the foreground I would like to measure the light intensity. According to ...
6
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1answer
2k views

How do filament LED bulbs work, looking very similar to incandescent bulbs?

Filament LED bulbs use very narrow strips containing the LED, which look similar to filaments of an old incandescent bulb. Here's a good picture: http://www.aruana-led.de/ They look like a normal ...
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0answers
23 views

CFL and CCFL difference: Can I use CFL balast like CCFL inverter?

I want to ask where is the difference in CFL (compact fluorescent lamp) and CCFL (cold cathode fluorescent light) in the meaning of thier elctrical circuit. I know it's two different types of ...
1
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1answer
449 views

Which diodes for 12v indicator light circuit?

Which diodes for 12v indicator light circuit? I have a car whose signal light audio indicator is too soft to hear. I would like to set-up an visual indicator on the dash for when the signal lights ...
0
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1answer
49 views

Detecting and identifying different light sources in arduino?

I want to detect different light sources in arduino. The first Idea about solving this problem came into my mind was to add three light detection sensors (LDR, IR receiver Diode and Photo transistor) ...
4
votes
1answer
98 views

Which photo sensor should I use in dust prone areas?

I am trying to automate the street lights near my house by using a photo sensor. But before even starting I thought of asking if there is any way of sensing light in dust prone areas, since I don't ...
1
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1answer
151 views

Photodiode Array Wiring

Sorry if this is a basic question. I would like to use photodiodes to precisely measure changes to light amplitude using an Arduino, similar to Figure 2 here: However, I would like to wire six ...
0
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4answers
108 views

Light sensor to sense light level

I have an application where I am trying to monitor a defect in a web based manufacturing process. This defect can be seen if one side of the substrate is lighted and the transmitted light is viewed ...
1
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4answers
351 views

Highly accurate constant current source

I want a continuous and highly stable light from an LED for around a couple of hours, for which I need a highly constant and highly stable current source. I prefer an opamp-based circuit for the same. ...
1
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1answer
122 views

How do external circuits in light switching units (such as Lightwave RF) use the mains wiring for power?

LightwaveRF is a simple switching unit that contains additional circuitry to enable automatic wireless switching. The additional circuit is powered by the mains light switching circuit. This is my ...
7
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1answer
172 views

Low-level light detection

I'm looking for the best way to detect a weak bluish light (440nm) in a dark environment - with "best" I mean with highest sensitivity possible. I've noticed that most LDRs and photodiodes have their ...
0
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3answers
147 views

Low Voltage DC controlling 120 AC, with Arduino

I'm looking for a type of device I can hook my arduino (micro-controller) to that will control a set of lights that require 120VAC. Basically I will be making a light organ, where the arduino will be ...
3
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2answers
165 views

Why do some power transistors emit light?

I am specifically looking for an image I believe I have seen before so I can link it to a friend. It was a TO-3 packaged device with the metal cap removed, showing a power device emitting light as a ...