Led Definition and 450 Threads

Hi! Question about LED power supplies. They all have marked ripple voltage. Typically 150mV. How much ripple voltage is human eye capable of noticing when looking at LED strips? And is there difference between 12V and 24V? I have opinion that 150mV ripple on 24V LED strip would give the same...

Summary: Will an external surface reflect light into a more focused beam without using a traditional lens? Hey guys. Just trying to focus the light coming from a 1watt LED light source. It's native beam angle is 130 degrees. I'm hoping to focus it to around 30 degrees. We are creating an...

There has been a large shift from energy inefficient lighting in the last 10 years to LEDs in domestic, retail stores, cars and council run buildings and street lights. The study in the link below by the French government agency support a previous study in 2012 by Sánchez-Ramos published...

Hi! I found interesting post here: https://electronics.stackexchange.com/questions/325762/how-efficient-are-leds However, it only gives the final results and not the steps he made. I tried to learn the formulas on wikipedia on my own but I couldn't figure out what variables need to have what...

Hey everyone, I recently came across UVC leds and was wondering if they could be used to disinfect water in a simple way. If I got a bucket with 5 litres of water in it, stuck a 50mW radiant flux UVC led (like this) on the lid and run it for 1 minute would that be enough time and power to...

Hello, Just out of curiosity I disassembled an LED GU10 light to see what's inside and found, a rectifier, a few capacities, and a small transformer. It was working fine before, but when I took the plate that has all the LEDs soldered to it and tired to power it on my DC variable power supply it...

I'm trying to optimize my vein viewer with LED lights but I'm not sure which factors affect the penetration of the light through the skin. (I'm following this guide https://www.instructables.com/id/How-to-make-an-affordable-Vein-Finder-for-use-d/) I can say those factors are the angle of the...

I am trying to design a LED driver that will be PWM controlled by Raspberry PI. Actually I already have a prototype (based on PT4115) and it works - kind of. I need to start with LEDs being off and switch them on only when they are needed. Unfortunately, both driver and Raspberry are powered at...

Thanks to anyone who likes to chime in and help out this newbie. :smile: I bought some CC CV buck converters to power my DIY LED panel project using a perfectly working PC power supply unit that was collecting dust inside a fairly old and unused PC but unfortunately the buck converter does not...

Hi! I'm new to EE and was wondering if this: https://imgur.com/a/lSgNl52 would cause the LED to light up, or would the transistor short the circuit? (I forgot to add the arrow on the diode and I'm too lazy to fix it. And I just realized that the resistor is wrongly placed.)

Homework Statement As the title suggests, I have a school project where I’m supposed to design a hand shake flashlight using AWG 34 copper wire, a niobium cylindrical magnet, hard paper (sort of like cardboard), and a red LED. The goal’s to get the red LED to light. My teacher gave some hints...

An item I want to buy comes backlit blue and I need it to be GREEN. I contacted the seller and asked if I could change the bulb color with a green bulb condom and asked if it was currently a clear led, with a blue cover. THey said yes, but later they then wrote me back saying they made a mistake...

I have studied the operation of light Diodes in the basic electronics course in my graduation and I had a question! Light Diodes (LEDs) are semiconductor materials with P-N junctions and that when energized emit visible light. I understand that the process of light emission when applying a...

Homework Statement Calculate the expected peak wavelength and spectral bandwidth (in units of wavelength) of the emission for both a GaAs and silicon LED at liquid nitrogen temperature (77 K) and room temperature (300 K). Which of these cases would you expect to result in the best emitter and...

When putting an LED in series with a Resistor do you put it according to current convention (positive to negative) or to the actual current flow? Does it matter?

Hello What is this led for in electricity meter

Homework Statement Hello, I have got input from comparator op amp which gives HIGH or LOW. Based upon that, one of two LEDs needs to light up. Two LEDs should't be ON at the same time. Calculations are not needed, only the schematics. Homework Equations None The Attempt at a Solution I am not...

I am trying to get relay to come on when it gets dark outside this works with one LED and 600 ohm resistor but it does not seem to turn on relay I get 20 ma draw when applying 12 volts to coil it seems you need transistor or SCR to to turn on relay. Relay I think was from a TV it's only 1/2" X...

I've been doing a lot of searching on the interwebs for the best way to power these 3W epistar high power LEDs. And then I started looking for an alternate I can afford. I hope someone can help me as I'm not too good with electronics. I got a handful of these LEDs...

Hi everyone! I am a new one to the world of the LED lights. However, I have an oncoming project with LED strips. There will be 3 separate runs of a LED strip (4 meters, 4 meters and 6 meters each). In each run LED strip will be put in 1 meter long LED strip profile. I am planning to connect the...

Where can i find schematic for my tv: ITT LED 32H-7175-B?

Hello, I'm new to electronics and I'm reading a book currently to learn more about the topic. I'm currently on a section where I'm building circuits where I'm using a transistor as a switch. I decided to experiment with the circuit they gave me and put it in a simulation software called Proteus...

So I was messing around and made a lemon battery using a zinc nail and a copper penny. I wired 4 of these lemons together and connected it to a 5mm red LED and got around 3.7V. It came on but was dim. However, when I wire my power supply and also set it to 3.7V, it is much brighter. Now i assume...

So, I'm new to electronics and I started to build some circuits with LEDs. I read up on how LEDs work and how they consist of a doped semiconductor material etc. But when I actually went to wire the LED in, it said the anode should be connected to the positive terminal of the power source. I'm...

Hello, I have found references giving the equation for an ABC model for GaN-based LEDs (see: file://icnas3.cc.ic.ac.uk/lsm16/materials-10-01233.pdf), but I am not able to find any for simple GaAs infrared LEDs (LED information: https://uk.rs-online.com/web/p/ir-leds/8108247/#). Does similar...

Any input on why LED's are not used in modern camera flashes/strobes? I've searched a bit and it seems newer multi-die LED arrays not only put out more light but can strobe faster than xenon lamps, sounds win/win? I feel I must be missing something?! I was considering trying to modify a small...

Hi everybody, I'm a curious worker and passionate student, I haven't got the possibility to study at the university but my passion for SSL lighting and light phenomena in general started some years ago, has helped me to start a long journey, trying to understand a little more day by day of what...

To begin: This is not a question, but an anecdote. The other day my wife called to me from the floor above: "Svein, there is no light". OK, I checked the fuses, and sure enough one fuse had tripped. I resat it, only to hear "Svein, it is blinking!". I went up to see what she meant by that and...

I would like to start growing plants in an artificial simulated environment with very low cost, hence i would like to know whether if i could vary the wavelength of light using a normal led light by varying voltage or current

Hi, Lately I've been reading about a lab exercise in which Planck's constant is estimated using LEDs. Every procedure I've encountered states that the energy of an emitted photon (and by extension the potential across the semiconductor's band gap) is equal to the threshold voltage multiplied by...

Lets say I have an LED that is being pulsed once every two seconds. The LED uses 5 mA of current each time its fired and the pulse lasts for 40mS. I know the current into the LED because I measured the voltage drop across the dropping resistor of 420 ohms with a good O-Scope. So I know all...

Homework Statement According to my textbook: The LED transfer function ##H(\omega_m)## is defined as: $$H(\omega_m) = \frac{1}{1+j\omega_{m}\tau_{c}}$$ The 3-dB modulation bandwidth ##f_{\text{3 dB}}## is defined as the modulation frequency at which ##H(\omega_m)## is reduced by 3 dB or by a...

Can you help me figure out how this light-based phenomenon works? Please explain with an intuitive answer using the simplest principles possible. Note how the location and width of the dark horizontal bands is constant with respect to the edge of the video frame. The LED light looks normal...

Hey, I want to ask you about the array led component: 1.9mm(0.8’’)8*8 blue dot matrix led displays (model no:KWM-20882XBA). << Edit by Mentor to add link to datasheet >>[/color] https://cdn-shop.adafruit.com/datasheets/956datasheet.pdf I saw the technical data sheet but I couldn’t find the...

Good morning and my compliment for their infinite knowledge contained in this forum. I'm struggling to keep being my girlfriend's hero. I have here a nail led 36w UV led lamp that failed last week. Bulbs are tested all ok and connected in two channels each channel in series of 9 LEDs of 2w...

Hi, Out of interest, today I was mucking around with a 160W LED, 240V, 50hz, outdoor light. I looked at the Power Factor (it was 0.96) and the THD was 14.something %. I then wondered what would happen if I put a capacitor in parallel with the light. It was a three phase 90uF cap, so since they...

Hi, I want to run a cheap 5 meter led strip along the inside of my boat for cool night lighting. It will be powered by a 12v deep cycle battery. I was hoping y'all could double check what I was thinking before I set something on fire... Here is the led strip...

hello everyone i thank you all in advance for reading this and i m hoping someone will be able to help me with this i got some led light strip to use as a tail light on my motorbike. i want to find a way to turn the tail light off when using blinkers.. and tail light back on when i turn...

Hello all. Thanks for taking up your time to read my post. I checked the currents that passed through several LEDs for MIC2287CBD5 as the datasheet of http://www.kynix.com/uploadfiles/pdf2286/MIC2287CBD5.pdf at a particular voltage. They varied from 12.0 to 15.1 mA at 3.0 V. I then connected...

Attached is a picture of my set-up. It is very simple and if for a car (12V) The LED kit comes with 3 options: Hard wire install, cigarette lighter install, and 9 + 9 V battery demo. The peculiar thing is when I connect the hard wire install plug (shown at the top of the picture) to a...

Saw an old thread, "Led Lights Burn With Power Off" and it was closed... so let me check out an issue with you all: in this same situation and I don't want the lights softly glowing, could I put a 100 ohm 1/4 watt resister in line to block the teeny tiny induced current? Would it behave well...

I want to design a yoyo that upon spinning, the energy from the spinning, can turn a mini generator inside and store that energy into a battery which then powers a LED inside. From basic calculations, I have seen that I could probably generate about 10W of power per 'toss' due to the high rpms...

Hi guys, I am trying to build a underwater camera system with lights. The depth requirement is 1500 feet. I need to view the bottom well enough to understand what conditions exist. I need to know if the bottom is rock or sand or mud. I have solved the camera issue...well I think...lol The...

I have a 4.5v LED strip 14.5watts (unknown amp draw; maybe 3amp) 30 LED 5050 per meter that runs off 3 AA Alkaline batteries. It runs fine for several hours (with the AAs) which is great but Id like to hook it up to a small power bank. I pulled out an old old power bank of 2200mAh 5v 1A output...

Homework Statement Attached to this thread is the question and mark scheme. Homework EquationsThe Attempt at a Solution I got most of the question right but I have no idea about the explanation part of why to include the 100 ohm resistor which is required for the higher level. It says in the...

Hi, I want to buy 5 meter 60 LEDs/m LED strip here and this is the recommended circuit. The strip needs 5V. In their description they say 60 LED is 18W so I need 20A DC power supply. Can I send 20A 5V DC directly in the strip? Will it fry the strip? Also, for the ground wiring, is this where...

First a little background. In my lab physics class we performed a lab to determine the Feigenbaum constant. I decided to do my research project on period doubling in non-linear circuits. I started thinking about the RLD circuit and how I could make it more interesting by adding different...

Hey All, i just joined today to try and figure out what size of diodes i need for the project I am working on. I am working on installing a new Light Bar and Flood Lamps to my Jeep to get better light at night. This is my hope to accomplish: Relay 1 will be used to turn the LED Light Bar and...

Hi. In this video around 6:45, this guy builds a simple dipole antenna with an LED and capacitor in parallel in the center. The LED flickers when close to a transmitting cellphone. Since the LED only let's current pass in one direction, shouldn't this quickly lead to a charge imbalance between...

Dear Every Smart Person, I am not a scientist or a physicist by any means, but I have a concept that has been literally driving me crazy all day. No matter how much I read, I can't make sense of it. Here it goes. I work in the LED Lighting space. In that space, there are two types of LEDs: a...