Multiple LED options and issues - personal visualization

194

01:50:53

Option 1: LEDs in parallel with single resistor (two different layouts).
This is not the preferred approach according to several other people and websites.
Each layout pulls 60mA from the power source.
Can survive LEDs going out as long as the remaining LEDs can withstand the increased current (60mA \ # of remaining LEDs).  If two LEDs fail, the remaining LED will need to withstand the full 60mA itself.

Option 2: LEDs in series with single resistor (two different layouts).
Least expensive method, but has a single point of failure.
Each layout pulls only 20mA from the power source.
Cannot survive any LEDs going out since they are in series.

Option 3: LEDs in parallel, each with their own resistor (two different layouts).
Most reliable, but most components and most complex (of these three).
Each layout pulls 20mA * working LEDs from the power source.
Each LED can survive the others going out and will maintain the same 20mA pull they had before others failed.
...I was also validating for myself that resistors can be before or after LEDs.

published 4 years ago

wyoelk

4 years ago

Try this website _ _ http://lednique.com/parallel-leds/ it explains these good and bad configurations

BillyT

4 years ago

In reality just check out the billions of Christmas lights sold each year, many different combinations of series and or parallel strings with nary a resistor in sight. How do they work ok? The designers use reasonable current choice in their designs, so that the loss or shortage of one device does not affect the whole string. The bottom line is, always run the leds at current that is a little lower than the data sheet recommends, even if the Max current they can run is higher.

NarWhale

4 years ago

Wyoelk: thanks, that summed it up rather nicely for me. Essentially, Option 1 = bad, Option 2 = less expensive, Option 3 = more reliable

NarWhale

4 years ago

BillyT: yeah... my family is getting a little concerned with the random broken devices that I refuse to throw away because I am still learning things or salvaging parts out of them.

NarWhale

4 years ago

I've made a few dodads and occasionally want to throw an indicator in somewhere. So far, because I don't fully understand how to control several different power levels, I tend to just throw a resistor and an LED somewhere in parallel to the load, or after a switch of some sort. I can't wait to learn how to properly control voltage and current levels.

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