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

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Variable Plug Outlet 110~120 VAC [on hold]

I have a lamp in my newborn son's room, and like many lamps, it's on/off switch makes noise, which he does not always like to hear when falling asleep. Do they already make some sort of TRIAC style ...
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2answers
49 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 ...
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1answer
54 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 ...
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2answers
73 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 ...
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1answer
98 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 ...
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2answers
423 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 ...
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1answer
151 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? ...
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1answer
65 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 ...
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1answer
186 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
182 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 ...
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1answer
82 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 ...
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2answers
275 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?
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1answer
53 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 ...
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1answer
86 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 ...
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1answer
51 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 ...
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2answers
94 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 ...
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1answer
43 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 ...
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1answer
367 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 ...
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2answers
157 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 ...
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0answers
45 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 ...
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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 ...
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1answer
74 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 ...
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1answer
965 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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20 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 ...
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1answer
261 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 ...
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1answer
46 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) ...
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1answer
92 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 ...
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1answer
121 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 ...
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4answers
100 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 ...
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4answers
303 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. ...
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1answer
96 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
171 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 ...
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3answers
129 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 ...
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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 ...
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1answer
77 views

Is a pin fin heatsink with 4 fans enough for 2x 80W LEDs

I need advice: I plan to use a heat-sink for cooling 2x 80W white LEDs over my friend's tank. The heat-sink is a "pin fin" design, 6 inches by 6 inches which combined with active cooling should ...
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1answer
56 views

Viability of an LED grid

I am a newbie with these type of applications, but I am trying to see if this idea would work out. Essentially what I am trying to do is build a large panel 2ft x 20ft that will act as one large ...
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2answers
203 views

Permanently dimming an incandescent light bulb

I have purchased a nice light bulb with long visible wires/resistors and plugged it in, on the ceiling. It burns too bright without a dimmer and does not look as intended (also the lifespan ...
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3answers
121 views

How to tell the lumen output of these LED's

I'm trying to build a light fixture for my aquarium, but I'm having difficulty understanding the various way manufacturers represent light output. I'm trying to compare the output of CREEXPE-ROY-3 ...
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1answer
74 views

What issues are there in designing a LED lighting system to replace Halogen G4 lighting

I wish to design a lighting system using electronics and LEDs as required to replace existing G4 Halogen lamps in order to increase available light levels in the available space. Situatiuon: Kitchen ...
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1answer
76 views

Looking for replacement LED [closed]

I'm looking for someone who can tell me what kind of LED this is (The barcode is: 5541475) It's the blue LED from this projector: Acer K135 I'm trying to modify the beamer and replace the LED with ...
3
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0answers
82 views

Preamplifier that responds to 10 kHz [closed]

I am having a problem of designing pre-amplifier that responds to light pulses of 10 kHz. I have designed the one below but I don't understand the scenario in which the output voltage builds up to a ...
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0answers
74 views

GPIO and light interrupter

I have a GPIO board on hand like this: I am a beginner to GPIO board and wish to seek some suggestions. I would like to connect a light interrupter / photointerrupter to one of the four inputs, but ...
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0answers
342 views

MOC3010 & BT136 with Arduino as trigger to power AC light

I've spend days debugging this circuit and have exhausted all possible solutions. I'm trying to use an Arduino PWM pin to light a 120V AC lightbulb. In order to do this I'm using a MOC3010 ...
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2answers
132 views

Convert Plugin Christmas decoration to a battery operated light

I have an old ceramic Christmas tree that I would like to convert to a battery powered source in order to get rid of the cord. Ideally I'd love to add a timer to it as well. I'm not sure what ...
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1answer
119 views

Have Pins light up after pushing a button/switch

I'm trying to create a "Push Pin" map for a friend as a gift. My friend has traveled through out the world and I'd like to organize the pins by year. So a different color pin for each year he has ...
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3answers
126 views

How to receive faint AM light

I am going to be amplitude modulating a high power LED light from a peak on a mountain. I want to recieve this faint light as far as physically possible before the light fades out too much to recieve. ...
3
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1answer
127 views

Improvized small aquarium lighting

I have a small aquarium that has been illuminated so far by a 15W fluorescent lamp. The problem is that the ballast has broken (melted) after 2 years of use, and the only replacements I could find on ...
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2answers
424 views

Can I shorten a length of C9 Christmas lights? [closed]

I have a string of 25 C9 LED Christmas lights, and I'd like to shorten the string. After untangling the string, they seem to be wired like this... simulate this circuit – Schematic ...
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2answers
211 views

Microcontroller Protection

I used microcontroller for wireless application. Problems arise when I put the microcontroller in high rainfall areas. The microcontroller is often damaged by lightning. How to protect data lines ...
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1answer
195 views

Using Arduino Uno R3 + Ethernet Module, how to control current pass to Lamps?

I have Arduino Uno R3 and Arduino Ethernet Shield V5. What's missing in order to control 6+ lights (bulbs) from my home? Those are connected to 220V AC. My idea is to send a packet via ethernet that ...