Questions tagged [light]

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

Filter by
Sorted by
Tagged with
1
vote
1answer
95 views

Can I make an LED turn OFF when current ON, and ON when current OFF?

Im an electronics noob so this may be a stupid question....but here's some context to my problem. I am rebuilding a motorcycle and have swapped out the dash. There is a wire coming off the bike to ...
0
votes
1answer
38 views

Finding the PPF and PPFD using a LED data sheet

I would like to design my own grow lights to grow indoor plants like strawberries, herbs, etc. But I have a problem that I need some help to work out: How many LEDs do I need to light up an area of 0....
2
votes
0answers
85 views

Help to understand the circuit function for me to repair - 30W LED ceiling light

I have a 30W LED ceiling light that has an adjustable LED temperature and is dimmable. It has a center lower power night light. It is controlled via an IR remote. I need advice on how to repair the ...
0
votes
0answers
70 views

Stray voltage on light fixture

I have installed a led panel on a previously existing light pole in my house. It has the feature of switching light colors if you flip the switch quickly. If the switch is left off for some time and ...
-3
votes
2answers
72 views

What LED color temperature should I choose? [closed]

I am planning to start a new company, but I don't have much funds. I am thinking about what led light should I choose as the light in the office area. Can it achieve the two conditions of being cheap ...
0
votes
1answer
47 views

Need help on solar light auto on off dawn to dusk

I have 36 Ah battery. I will charge it through solar change controller or through inverter. I want to connect this battery to two 9 watt DC LED garden lights which will turn on and off automatically ...
0
votes
1answer
55 views

My "Sun up" circuit is malfunctioning in circuit, but works fine on USB test bench

I am trying to build a circuit to use the Arduino Uno R3 as a switch for a relay which makes a connection only during daylight. I don't know much about my LDR, pretty sure it is a 10K. I am dividing ...
0
votes
2answers
229 views

Glass of microwave oven

From a user who "doesn't know" anything about Maxwell's equations. How to explain simply the behavior of a transparent glass of a microwave oven? Lets the light pass ... but blocks the "...
0
votes
2answers
51 views

Trying to measure solution's color intensity. Is there any way to stop voltage variations?

I am trying to build a spectrometer to measure the color intensity of a solution. By chemistry I can make up a solution that has exactly 1 mg of gold in it and another that has 5 mg of gold in it. If ...
0
votes
2answers
42 views

Adjustable Sensitivity in a Light Sensor Circuit

I've designed the following circuit for detecting light and darkness and it seems to be working fine. I want to be able to set both LEDs to be off at a particular light sensitivity and to only come on ...
0
votes
1answer
72 views

I Need Help Making a Weird Custom Flashlight

As said in the title, I am trying to make a homemade flashlight. I have no experience when it comes to electrical engineering and I have a very basic understanding of this stuff. What I am trying to ...
0
votes
0answers
47 views

Parallel light failed to work, one light get's blow other remains good. How to get it working?

I'm using a mobile battery (4V) to power the two (each takes 3.0V) light in parallel since series circuit won't work with one battery. After connecting the wire, for a short time it did work. Then one ...
0
votes
2answers
69 views

How good are Time-Of-Fligt (light) sensors for measuring small objects?

I found this sensor VCNL4040 and it has the emitter angle and the sensor angle. Question: How good is a Time-Of-Flight (light) sensor to measure small objects that are 100mm away and about 20x20mm in ...
0
votes
1answer
38 views

How wide is IR-led light from VCNL4040?

I have an issue to solve. I'm going to measure an object that looks like this. My question is if the sensor VCNL4040 have a very wide spread light or very "laser-like" light that ...
0
votes
0answers
15 views

12VDC 3-Position Axial/Rotating Connector

I am looking to source a connector suitable for use in a 12VDC light. I need to assemble/disassemble the 3 components- a base, stem and head. The 'tricky' part is that I also want these connectors to ...
0
votes
1answer
36 views

Changing a homemade LED light (14V Battery Pack) to run off mains?

I've got a wee challenge on my hands. My ex-girlfriend gave me this light as a b-day present 3D printed. I've been told that the LED is a 10mm Ultrabrite LED. See the picture attached for the battery ...
0
votes
2answers
45 views

Need help with configuration of a touch sensing lamp project! [closed]

I am currently a design student in university, and am attempting to configure a large scale project for my final. The idea is that there would be a lamp, with one person holding onto either (wire? ...
0
votes
1answer
73 views

What is a single-flash transistor-and-capacitor circuit actually called?

The internet is awash with diagrams where two lights alternately flash with the aid of transistors and capacitors. However, I remember at school being shown an introductory circuit in which one light ...
0
votes
1answer
104 views

Backfeeding MCU gate output bad?

I am trying to modify a work light (1S3P 18650 3,6V) that is controlled by an 8 pin PADUK type micro. An output from the micro goes through a 100 Ohm resistor straight to the MOSFET gate. It has the ...
2
votes
1answer
47 views

LCD prints black text on blue screen, but can print white on blue when bugged out

I am using the esp8266 which can supply 3.3V to power on an LCD 16x2. However, I am running into trouble regarding the visibility of the LCD's contents. The LCD prints black text on a blue background ...
26
votes
7answers
4k views

Is it possible to generate light with an antenna?

An antenna (e.g. a dipole) is able to radiate at a certain frequency thanks to the EM field generated by a current provided by a signal generator at such a frequency. So, for instance: Voltage source ...
-1
votes
5answers
115 views

Alternating current frequency

An introductory discussion of alternating current in a primer I was taking left me thinking. We don't see a light bulb flicker because the alternating happens at 50-60 Hz. If it takes 1.28 seconds for ...
0
votes
0answers
15 views

Trailer Light Conversion Module Not Working

I have a module with the attached schematic that I'm testing. On the left is the "vehicle" and the right is the "trailer" I don't have a load on the left side just inputting ...
0
votes
1answer
35 views

VCSEL to project a 2D array of dots [closed]

Background Apple iPhone Face ID uses VCSEL inside its dot projector to project infrared dots into a person face. Then an infrared camera captures the pattern to be used in a structured light algorithm ...
-1
votes
1answer
42 views

Transmitter & receiver circuit for high voltage lights

I want to control my room's lights by wireless circuit - like RF or whatever. In my country, the lamps and lights work on 220V AC. I'm still beginner, I have done this before and it worked, but by ...
0
votes
2answers
69 views

Red laser that has a higher power output at 400nm than 623nm?

I am doing experiments using a red (623nm) LED. However, when I measured the power output I noticed that it is higher at smaller wavelenghts. I did the measurements using two different power-meters ...
0
votes
1answer
67 views

Cleanest way to solar-power a string of outdoor bistro lights

I'm trying to hang some bistro lights on my balcony — specifically, the SVARTRÅ outdoor bistro lights from IKEA. There's just one issue: the balcony has no power outlets, and I'm not going to snake a ...
0
votes
1answer
90 views

Lightest possible USB solar charger with 5V 2A to 3A output?

I'm doing a lot of wilderness expeditions an needs the lightest gear possible. I want to make a solar charger (for my nitecore nb10000) that is as light as possible and has a USB output 5V and between ...
0
votes
2answers
92 views

Examples of using a circular polarizer filter for LED display

I was looking for ways to increase the contrast of a LED-based seven-segment display like this against indoor ambient light, and found this comment on EEVblog suggesting using circular polarizing ...
0
votes
0answers
23 views

Can 85V 35W ballast support a 85V 50W bulb

I am having PHILIPS MPXL DL50/740 85V 50W PX32D but not having a suitable ballast to test it. I am not able to find suitable ballast but ran into a 85V 35W ballast will it support? Is there any other ...
2
votes
1answer
253 views

Accuracy of manufactured photocells (LDR) with respect to light intensity

I was looking through photocell (photoresistors) datasheets, like for instance the NORPS-12, especially the graphic on resistance value versus light intensity. In no datasheet could I find information ...
-3
votes
4answers
124 views

What is waving in light? [closed]

I've been building an AM transmitter and it's generated a lot of questions. At the top is the electromagnetic wave. It may seem simple but I've yet to find an answer. As far as I know, light is made ...
-1
votes
5answers
141 views

Alternating green and red LEDs circuit

I tried to design this without much success so any help would be appreciated. A circuit where initially in a 3-pin Bi-Color LED (Common Cathode), the red led illuminates. Then it switches off and the ...
0
votes
0answers
78 views

IR beam break sensor

I want to make an "IR beam break sensor" as per attached schematic. I would also like to add some sort of “time delay” to the schematic. When the beam breaks and the relay gets activated, I ...
0
votes
2answers
108 views

How can there be voltage across resistors in series when circuit is open?

If you have a circuit containing 5 resistors, and one of them gets damaged such that current can't flow through it, I assumed no current would flow anywhere throughout the circuit, and that the ...
0
votes
1answer
2k views

Why is my 50-600V voltage tester able to detect 3V? [closed]

I used non-contact voltage tester to test burned out Christmas lights. It says it can only detect in the range of 50-600V. One of the strings has 40 bulbs in series and none of the lights are burned ...
0
votes
0answers
34 views

Coin cell UV pendant Q2 [duplicate]

I am a beginner with LED lights, but would like to use a 5mm 365nm UV LED diode to make a pendant with a small fluorescent crystal. I would like to create a very simple, very compact circuit with a ...
0
votes
4answers
50 views

Controlling a single lightbulb from multiple switches

It is quite common to have a single lightbulb in the home that has two switches to control it. It works so that whichever way the light is (on/off) you can change the state of either switch and it ...
2
votes
1answer
123 views

Coin cell to power a 5mm UV LED?

I am a beginner with LED lights, but would like to use a 5mm UV LED to make a pendant with a small fluorescent crystal. (This is what I purchased (https://www.amazon.com/uxcell-365-370nm-Ultraviolet-...
1
vote
1answer
71 views

What is the name of this item contact pin?

I am making a box with lights inside of it. These lights are UVC lights, which will sanitize any items put inside. I have attached a photo; I would like to know the name of this item. I know it is ...
0
votes
1answer
75 views

Difference between \$\epsilon\$ and \$\epsilon_0\$?

I have been given the following equation for the speed of light: \$V = \Large {1 \over {\sqrt {\mathstrut \epsilon \cdot \mu}}} = {1 \over \sqrt{\mathstrut \epsilon_0 \cdot \epsilon_r \cdot \mu_0 \...
1
vote
2answers
170 views

Would connecting multiple light socket splitters together decrease lumens

Sorry if this is a noob question. I'm trying to build a very bright light by combining multiple light bulbs together with socket splitters. My thinking is simply to take three 7 in 1 light socket ...
3
votes
2answers
229 views

How can electrons in a tungsten filament release infrared light photons?

I have a question regarding electric circuits, specifically when it comes to converting electromagnetic energy into light in a light bulb (tungsten)filament. How can an electron in a tungsten atom of ...
0
votes
0answers
16 views

How to measure intensity (lumen) of a light source?

Let's say I have an x800 cree LED (which was supposed to be 4000lumen) and a cheap lux-meter (thinking of buying one like this). My question is, which is the physical setup to measure the true ...
1
vote
1answer
99 views

10cm tube light source (see photo) - what is it?

I'm just trying to work out what this is: Neither the tube nor the blue box has any markings whatsoever that I can see. The tube is about 10cm long and appears to be transparent plastic with white ...
0
votes
4answers
143 views

Light sensor detecting when the lights turns on AND when the light turns off

I would like to create a circuit using photodiode that detects when the lights turn on AND when the lights turn off. The output should look something like that: I want to create the simplest possible ...
0
votes
0answers
25 views

Finding a XT60 connector switch with indicator lights

I'm looking for an XT60 connector switch (e.g. https://www.amazon.com/gp/product/B07K33LRW2/r), but need one with an indicator light so I can visually verify whether a current is flowing through the ...
-1
votes
2answers
125 views

I’m an electrical idiot - can you help me?

I have overhead doors at the back of my office building. I wanted to wire up a large red LED next to the light switch so that when employees leave, the light would be red indicating the doors are up. ...
1
vote
0answers
60 views

temperamental LED light

I have installed LED tubes in my kitchen ceiling light. They replaced the old fluorescent tubes. I removed the ballast and wired the fixtures according to instructions which essentially connected the ...
0
votes
2answers
58 views

Determining current through LED light

Not an electrical expert so please bear with me. I bought a no-name brand LED lamp that I would like to use with my 9V DC adapter as power source. The lamp uses 3 AA batteries in series. Batteries ...

1
2 3 4 5
10