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How does a voltage divider circuit to run an LED?

Posted: Mon Jun 07, 2021 2:34 am
by Markkim
Hi, all
Recently, I have a system running at 62V max, 54V nominal based on voltage divider formula (formula source https://www.apogeeweb.net/electron/what ... -rule.html). I wanted to have a little alert LED, so I was thinking about using 10, 1kohm resistors, and adding the LED bewteen the 9th and 10th (or 1st and 2nd, if it matters), to get at most 6V and just a few mA.

Is a better/easier way? Is this a really crappy way? Or is this a perfectly fine way?

Re: How does a voltage divider circuit to run an LED?

Posted: Mon Jun 07, 2021 3:19 am
by dyarker
A "regular" indicator LED is commonly 20mA maximum. Design for about 17mA.
The forward drop of an LED depends on color. 1.8V for red, to 3.8V blue, other colors in between.

Suggest you calculate 62V for 19mA through LED. That leaves a margin for a little over 62V, and 54V long term safe. If that it too bright, lower current is okay. (below 5mA LED may not light)

Cheers,

Re: How does a voltage divider circuit to run an LED?

Posted: Mon Jun 07, 2021 2:10 pm
by dacflyer
Perhaps this might help you ???
http://ledcalc.com/