Questions tagged [light]
Light is a tag about anything generates photons in the visible spectrum
512
questions
-1
votes
0
answers
37
views
Building light-sensing circuit
I need to build the above light-sensing circuit that can convert light into electric current, but I'm not sure about the part circled in red. Is it just a wire connection? Could you let me know the ...
0
votes
1
answer
70
views
Can usb power a 40W led light? [closed]
I've recently came across some usb led grow lights that are rated up to 40W. My question is how does a regular usb 2.0 or even 3.0 be able to power it? Is it a scam?
3
votes
1
answer
119
views
Light reading diode?
I’m trying to think of a device to measure amount of UVA & UVB daylight for plants in my shed and so trying to work out what I could use to measure:
The amount of light
Its type
Its time
Be able ...
- 31
-3
votes
1
answer
86
views
Can LEDs produce light like incandescent light? [closed]
LED light flickers around 100 Hz and is caused by rectifying AC power. How can LEDs be made to emit constant light that comes from an incandescent element which does not flicker?
0
votes
3
answers
81
views
Open circuit photodiode energy
Where does a photo-diode use the energy it collects from light and other EM waves when not loaded? Does it dissipate it as heat, reflect it or something else?
- 101
4
votes
1
answer
128
views
LED light transmission through prepreg in a PCB
I've designed a LED board 8x8 where LEDs are assembled in reverse. So, there is a through hole at every LED position, LEDs assembled at the bottom, and light goes through the PCB hole and comes out ...
user317023
1
vote
1
answer
21
views
Looking for a simple circuit to switch power to IR LED's at night (2A @ 12 volts)
I'm looking for a simple and cheap way to switch power to a few hi-current IR led's at night. So some sort of photo detector and a solid-state or traditional relay. Unless there's a single-component ...
- 129
1
vote
2
answers
82
views
What is this solar path light component?
Just for fun and curiosity, I decided to reverse engineer an old, cheap solar path light. It's a fairly simple circuit, but there's a component I can't find any information on. It has transistor-style ...
- 273
0
votes
2
answers
77
views
Mixing light from multiple leds
I'm trying to design a device that produces visible light with a somewhat controllable spectrum. My goal is to measure the human eye cone cell responses by switching between two different spectra and ...
- 103
-2
votes
2
answers
137
views
How do seven segment displays show black numbers?
Usually, seven-segment displays emit red coloured light, which is understandable. But in digital watches, the common colour used for the numbers displayed is black.
But black light itself can't be ...
- 3
1
vote
1
answer
56
views
IR LED Safety: Subtend Angle and Retinal Exposure Limit
The relevant formulas from OSRAM AN090 "Eye safety of IREDs used in lamp applications" with slight modifications :
$$ Z = (l + w)/2 $$
$$ \alpha = Z/d $$
$$ L_{ir} \approx \frac{I_e R(\...
- 11
0
votes
0
answers
36
views
How to change the wavelength of LEDs in Proteus?
I have a problem in designing a circuit for my project.
Can anyone explain how to simulate an LED with 940, 1550, and 1650 nm in Proteus software?
Dors the emission coefficient of LEDs in Proteus help ...
1
vote
1
answer
105
views
How to calculate the total power of a LED using solid angle?
I have a LED with the max power of 130mW/sr and an opening angle of +-10° (so approx. around 20°). I conducted an experiment using this LED, the LED shines light to an un-doped silicon semiconductor ...
- 11
1
vote
3
answers
154
views
Why are metal halide bulbs always ~130V?
I noticed that - even though the local voltage is 240V - metal halide bulbs are always sold as 130V bulbs, and their product sheets list the maximum voltage as 130V. Do perhaps all flood lights that ...
- 111
1
vote
0
answers
53
views
Incandescent light bulb in proteus
How to create a simulation model of The incandescent light bulb in Proteus?
- 11
1
vote
1
answer
140
views
What is this through-hole component holder used on aluminum PCBs?
I've been buying these cheaps LED lightbulbs and tore them down to see how the LEDs are driven.
On all of them I have found this surface mount component that allows a through hole component (here a ...
- 71
0
votes
0
answers
46
views
Creating ZigBee RGB Compatible Light - Raspberry Pi
I currently have a Rasberry Pi hooked up to a 64x32 LED matrix. It runs some custom Python scripts to control the colour and display of the matrix, which works great and lets me adjust the settings ...
3
votes
5
answers
883
views
What is the mathematical relationship between the resistance of an LDR and light intensity in lux?
I have been surfing the internet and my physics books for the relationship between the resistance of an LDR and light intensity (a formula), and so far I have found nothing.
If any of you have a ...
- 31
4
votes
7
answers
897
views
Is it possible to control the frequency of light?
I mean, controlling directly in the source, not filtering the light or arranging density of the medium. For example, brightness can be controlled by current or voltage directly. However, when I came ...
- 69
0
votes
1
answer
46
views
Photo Diode Receiver
I have designed a 5KHz Photo Diode Receiver circuit that Consists of a number of blocks. first stage of this circuit is a TIA.
I have problem with DC IR Light (Like SUN Light), when sun light shine on ...
2
votes
3
answers
1k
views
Why did this fog lamp turn on with either configuration of power/ground? [closed]
My friend and I were replacing a burnt out fog lamp on his car. When it was time to make the connection, I wanted to make sure which wire was power and ground, so we don’t cause a short to the new ...
- 139
1
vote
1
answer
78
views
Antiparallel LED Fairy Lights Hack
I have this string of USB powered LED fairy lights that came with an IR remote. I had initially planned to plug these into a smart outlet, using a phone charger adapter, in a place that isn't easily ...
- 11
-7
votes
1
answer
95
views
I have to build an LED lamp with a lithium battery [closed]
I don't understand much about electronics, I just know that the battery is very dangerous. These are the links of the components that I will use:
BATTERY 3.7V 4400mAh
LED 11,9V 1050mA
STEP UP BOOST ...
0
votes
1
answer
68
views
0
votes
8
answers
285
views
Using 110 Vac incandescent light bulb at 220 Vac with a series diode
I have a 110 Vac incandescent light bulb but I need to use it in 220 Vac.
If I add a diode in series with the bulb, the RMS power is the same as before but the peak value of voltage and current is ...
- 11
0
votes
3
answers
135
views
NAAAILTAC: Not another "add an indicator light to a circuit' question
There's quite a few places online where you can find out "how to add an indicator light into an existing circuit," but I can't find any that tell WHY the light needs to be added in a certain ...
- 17
2
votes
3
answers
418
views
Help identify IC
This is an LED light from AI, PRIME 16HD model.
I have identified the IC that seems to be burned; it looks like it's some kind of voltage regulator. I think the markings are: BN0D 18.
Maybe someone ...
- 31
0
votes
4
answers
132
views
How can a lidar achieve cm-level resolution?
In order to achieve cm-level resolution, it seems like a lidar would need to have extremely high sampling rates. Here's my thinking:
Light travels at roughly 3·108 m/s, or 3·1010 cm/s. We need to ...
4
votes
2
answers
785
views
How do the non-circuit old Christmas lights flash?
I have a 80's Christmas incandescent light string without any kind of electronics. They are static until you replace one normal bulb with one marked bulb.
It seems to be that the marked bulb (that ...
- 175
0
votes
0
answers
43
views
Transparent displays that allow UV light/sunlight to pass through them?
Is there a type of digital display that can work to let sun through it, so that the dark pixels block the UV, and transparent pixels let the UV through?
I'm aware of monochrome LCDs for a resin ...
1
vote
0
answers
60
views
What is the possible reason that cause the failure (burnt) of PTC in an electronic ballast?
What is the possible reason that might cause the failure (burnt) of PTC in an electronic ballast?
I have been using this VOSSLOH SCHWABE brand electronic ballast and recently it has been burning up ...
- 164
1
vote
1
answer
108
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
1
answer
156
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....
- 227
2
votes
0
answers
118
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 ...
- 39
0
votes
0
answers
139
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 ...
- 1
-3
votes
2
answers
73
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 ...
- 11
0
votes
1
answer
106
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 ...
- 21
0
votes
1
answer
57
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 ...
- 19
0
votes
2
answers
246
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 "...
- 7,151
0
votes
2
answers
60
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
2
answers
178
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 ...
- 1
0
votes
1
answer
76
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 ...
- 3
0
votes
0
answers
59
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 ...
- 11
0
votes
2
answers
85
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 ...
- 915
0
votes
1
answer
43
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 ...
- 915
0
votes
1
answer
41
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 ...
- 1
0
votes
2
answers
49
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
1
answer
149
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
1
answer
158
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 ...
- 775
2
votes
1
answer
154
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 ...
- 3,183