OT - electronics question
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
Are you thinking of a zener diode or voltage regulator? If you can describe the application, it may be easier to recommend the best way to power the LEDs. How long is the string of LEDs? You can run LEDs in series, and each LED (other than some red LEDs) will drop 3V per LED. As a roughly calculated example, that means that 20 LEDs in a row in series, connected to a 60V source, will light up properly. Although there should be some sort of single current limiting resistor in the circuit. On Wed, May 24, 2017 at 1:42 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
no there is a new component that helps one avoid zener diodes and voltage regulators. It was a "new" to me at least I had never seen one of these things before. Saves a lot of money and wiring On Wed, May 24, 2017 at 2:01 PM, Jeff Salzman via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Are you thinking of a zener diode or voltage regulator? If you can describe the application, it may be easier to recommend the best way to power the LEDs.
How long is the string of LEDs? You can run LEDs in series, and each LED (other than some red LEDs) will drop 3V per LED. As a roughly calculated example, that means that 20 LEDs in a row in series, connected to a 60V source, will light up properly. Although there should be some sort of single current limiting resistor in the circuit.
On Wed, May 24, 2017 at 1:42 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
You probably want a constant current source. Thanks, Jonathan On Wed, May 24, 2017 at 2:20 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
no there is a new component that helps one avoid zener diodes and voltage regulators. It was a "new" to me at least I had never seen one of these things before. Saves a lot of money and wiring
On Wed, May 24, 2017 at 2:01 PM, Jeff Salzman via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Are you thinking of a zener diode or voltage regulator? If you can describe the application, it may be easier to recommend the best way to power the LEDs.
How long is the string of LEDs? You can run LEDs in series, and each LED (other than some red LEDs) will drop 3V per LED. As a roughly calculated example, that means that 20 LEDs in a row in series, connected to a 60V source, will light up properly. Although there should be some sort of single current limiting resistor in the circuit.
On Wed, May 24, 2017 at 1:42 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
Typically, you drive a string of LEDs with a current source. The ones I buy on eBay (from Chinese sellers) typically are rated at XXmA for a range of voltage. For example, one might be rated at 20mA at 30 to 45 volts DC output. This means that you can drive a string of (about) 15 to 22 LEDs (assuming 2.0 V drop per LED) with 20mA through the string. Of course, the input voltage is also spec'd: 110vac, 220vac, etc. Here's a typical listing: ebay item 122480543106 Bill Dudley This email is free of malware because I run Linux. On Wed, May 24, 2017 at 2:20 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
no there is a new component that helps one avoid zener diodes and voltage regulators. It was a "new" to me at least I had never seen one of these things before. Saves a lot of money and wiring
On Wed, May 24, 2017 at 2:01 PM, Jeff Salzman via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Are you thinking of a zener diode or voltage regulator? If you can describe the application, it may be easier to recommend the best way to power the LEDs.
How long is the string of LEDs? You can run LEDs in series, and each LED (other than some red LEDs) will drop 3V per LED. As a roughly calculated example, that means that 20 LEDs in a row in series, connected to a 60V source, will light up properly. Although there should be some sort of single current limiting resistor in the circuit.
On Wed, May 24, 2017 at 1:42 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
no there is a new component that helps one avoid zener diodes and voltage regulators. It was a "new" to me at least I had never seen one of these things before. Saves a lot of money and wiring
Buck boost converter type thing? There are all sorts of drivers for LEDs now. https://youtu.be/WsWwpR9TsjQ?t=8 LED strips are dirt cheap from China. This is my 9' wide x 3' high RGB LED video wall currently sitting in my kitchen, uses 480 amps @ 5V worth of power supplies: https://www.youtube.com/watch?v=ReXP6luDKJw
You can build a programmable current source with the LM317 adjustable voltage regulator -- there are many examples of doing this for LED drive out there. The LM134/234/334 are purpose built for the task. Thanks, Jonathan On Wed, May 24, 2017 at 3:19 PM, Ethan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
no there is a new component that helps one avoid zener diodes and voltage
regulators. It was a "new" to me at least I had never seen one of these things before. Saves a lot of money and wiring
Buck boost converter type thing?
There are all sorts of drivers for LEDs now.
https://youtu.be/WsWwpR9TsjQ?t=8
LED strips are dirt cheap from China.
This is my 9' wide x 3' high RGB LED video wall currently sitting in my kitchen, uses 480 amps @ 5V worth of power supplies: https://www.youtube.com/watch?v=ReXP6luDKJw
On Wed, May 24, 2017 at 1:42 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
There is a "thing" that one can use to regulate LED voltages in a string, with a pretty large voltage/resistance variation. It's better than having a resistor at each light. What is this thing called?
Did you really mean voltages or the brightness levels, Not sure which kind of LEDs you were talking about In case of the RGB Leds, there's the PCA9685 I2C 12bit PWM 16channel controller, it would generate the RGB voltage levels to give you thousands of colors And this can be ganged together over the I2C serial bus to get even more channels, 100's of them But the newer neopixel RGB strings even have this chip built right inside each LED to save even more space and wiring Dan -- _ ____ / \__/ Scotty, We Need More Power !! \_/ _\__ Aye, Cap'n, but we've only got 80 col's !!
participants (6)
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Dan Roganti -
Ethan -
jsalzman＠gmail.com -
systems_glitch -
william degnan -
William Dudley