Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [brightness]

Brightness is an attribute of visual perception

Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. This is a subjective attribute/property of an object being observed.

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Circuit to create X levels of brightness for a LED

If I'm here today, it's because I need some help for something that is, I think, easy for you. I am quite a newbie in EE but I am trying to improve myself :). Here is the thing, I'll try to be as clear as possible with what I am dealing with. I am…
vionyst
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LED blinking with capacitor and schottky diode?

I saw one circuit which connected one 100uF capacitor and one schottky diode as mentioned in the below circuit diagram. It has a negative logic rectangular pulse at cathode of the LED, which is providing ground for the LED. I tested that circuit…
Deepak Aagri
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Simple LED fade circuit

I've been looking for a simple LED fade in/fade out circuit when power is turned on/off for a 12 V LED. I have tried the following circuits but the problem is that I can't reach the full brightness of the LED that it reaches when simply connected to…
Electric_90
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How Is Intensity of Blue Light Measured?

As a hobby project and to help solve issues getting up early in the morning (specially given that it's winter and the sun isn't up until long after I am) I'm trying to find a bright blue light that I can put on a dimmer. I've read that the eye (even…
azoundria
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Estimating apparent LED brightness: current or power?

TL;DR - based on the physics of LEDs, does current or power give a better estimation of actual light output of an LED? I am building a dimmer circuit with a few discrete steps, to operate a COB LED from a constant-current source. I want the steps…
JAE
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Choosing an LED

a friend has asked me to help them with a LED billboard type of art piece. It's envisioned to basically be ping pong balls cut in half with LEDs mounted under them. She got some jumbo (10mm) LEDs for their brightness specs, and she's happy with the…
vicatcu
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How to compare brightness of different color LEDs (not RGB)?

I wonder - let's assume one would build some user interface using green, yellow and red or just any other available colored LED (not RGB LED) - what would be the proper (aka best) way to compare the brightness of LEDs in order to choose "equally…
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How does area and intensity relate to perceptive brigthness of a light source?

I want to design tail-lights for onboard use in vehicles (mostly bicycles), but I wonder how should I configure the system so as to get the best visual perception from a distance. Each lighting element of the system would be composed of a number of…
heltonbiker
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LED strip brightness and its measurement - did I get ripped off?

I recently bought two 5m rolls of red and blue LEDs for building an hydroponic lettuce light. Each of them is supposed to have the following properties: 300 SMD 5050 LEDS 72 Watts 12 Volts 4500 Lumens Beam Angel 120° See Amazon Naturally the high…
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Regulate brightness over video composite signal

I have a b/w camera that outputs a video composite signal. At night it works very well, but during the day it's so bright everything just turns white. Is it possible to add a potentiometer to be able to dim the brightness? If so, what resistance…
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Safety regulations (USA) for high-power LED brightness (e.g. 1+ W)

For a "mostly" shielded sequence of 1 W where a user will see light bleed through small gaps in a device and (for argument's sake) might see a direct reflection of one of these 1 W LEDs (a multi-die LED with red and green sources), are there any…
chroma
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Measuring display brightness decay

Our device is specified to have a display brightness of 500 cd/m² and it must not decay to less than 50% brightness in 50,000 hours. Now, I can't wait for 5.7 years for that test to finish. I guess that this issue has been solved before. How is…
Thomas Weller
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How to add lumens

I have n bulbs of luminosity k in fixture a. How many bulbs of luminosity l do I need in fixture b for the brightness of a to match the brightness of b? Specifically, I'm wondering how many standard LED components I would need to approximately…
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Is there a simple way to diffuse the light of a "super bright" 5mm LED?

I want to put yellow leds inside the turning-signal cases used in motorcycles. The problem is: since the case is not deep enough, when I look from far I can only see the focused, pin shaped LED sources (two, in my case). The leds I am using are like…
heltonbiker
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EL wire brightness, per m not per m\$^2\$

The datasheets and catalog pages for commercial electroluminescent (EL) wire in hobby quantities, e.g., adafruit's, list brightness in candelas per square meter. That's ok for two-dimensional EL sheet, but not for one-dimensional wire. (I…
Camille Goudeseune
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