led primer
led primer
Can someone suggest a reference regarding the various types of leds and and their current and voltage requirements? I've seen advertisements offering leds with various degrees of brightness and sizes and wonder if they have different requirements? Thanks Paul
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Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
LEDs generally start at 20 milliamps.
Voltage is dependant on the LED.
They do go higher up to 45 mills, white etc, but other than the white style, you can pulse them by using time.
One half the time, twice the current, 100th the on time,... 100 times the pulse amps.
There are very few limits other than your equipment.
Leds can be pulsed in the amp range of 10s of amps, or even 100s of amps, with times of 500 ns, 200 ns, or even 10 ns.
1000 times a second or different.
Voltage is dependant on the LED.
They do go higher up to 45 mills, white etc, but other than the white style, you can pulse them by using time.
One half the time, twice the current, 100th the on time,... 100 times the pulse amps.
There are very few limits other than your equipment.
Leds can be pulsed in the amp range of 10s of amps, or even 100s of amps, with times of 500 ns, 200 ns, or even 10 ns.
1000 times a second or different.
I agree that current and voltage specs are the most important electrical specs. Look for a typical rating and a maximum. The max may contain notes about heat sink or other thermal concerns.
To add to that is the power rating of the package which determines how far you can go without damage or degrading the lifetime. Overdriving the LED by pulsing is common but I think 100s of Amps and 10s of ns is pushing whats realistic but maybe an esoteric application, who knows
Additionally there is color, brightness and angle of light dispersion and reliability to be concerned with on the physical level. Some brighter and higher wattage devices require a heat sink particularly SMT mount devices to achieve maximum rated performance and full lifetime.
Typical indicator LED devices may have skimpy spec sheets with minimal information but the more advanced brighter and whiter LEDs have app notes and everything you need to know.
Today I would divide the market between indicators/displays and illumination products. Indicator LEDs have a huge variety of package sizes and colors and brightness but generally are small and lower current devices not requiring heat sinks. Alpha and numeric displays are just fancy indicators. This is the mature part of the LED market.
You guessed it, illumination LEDs are brightest, whitest, have special thermal mounting considerations and are most expensive. But they are the fastest developing segment and soon to be the fastest growing market for LEDs.
There is some overlap between these two like very bright indicators used as keychain flashlights. and Im not sure where I would place a traffic light, the components are indicators but the assembly is a lamp. But that's just my observed POV others may divide it up differently.
As for a reference. The best I use are the physical paper copies of the DIgikey and Mouser catalogs and occasionally others. Notably their websites have selection filters based on common specs to narrow and catagorize the market. Best part is the search results usually lead to a manufacturers datasheet (grass roots of all technical info) . This advice goes for most components. My copies would be dog eared if they didn't send me six a quarter.
To add to that is the power rating of the package which determines how far you can go without damage or degrading the lifetime. Overdriving the LED by pulsing is common but I think 100s of Amps and 10s of ns is pushing whats realistic but maybe an esoteric application, who knows
Additionally there is color, brightness and angle of light dispersion and reliability to be concerned with on the physical level. Some brighter and higher wattage devices require a heat sink particularly SMT mount devices to achieve maximum rated performance and full lifetime.
Typical indicator LED devices may have skimpy spec sheets with minimal information but the more advanced brighter and whiter LEDs have app notes and everything you need to know.
Today I would divide the market between indicators/displays and illumination products. Indicator LEDs have a huge variety of package sizes and colors and brightness but generally are small and lower current devices not requiring heat sinks. Alpha and numeric displays are just fancy indicators. This is the mature part of the LED market.
You guessed it, illumination LEDs are brightest, whitest, have special thermal mounting considerations and are most expensive. But they are the fastest developing segment and soon to be the fastest growing market for LEDs.
There is some overlap between these two like very bright indicators used as keychain flashlights. and Im not sure where I would place a traffic light, the components are indicators but the assembly is a lamp. But that's just my observed POV others may divide it up differently.
As for a reference. The best I use are the physical paper copies of the DIgikey and Mouser catalogs and occasionally others. Notably their websites have selection filters based on common specs to narrow and catagorize the market. Best part is the search results usually lead to a manufacturers datasheet (grass roots of all technical info) . This advice goes for most components. My copies would be dog eared if they didn't send me six a quarter.
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