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Author Topic: Help fix LED flicker  (Read 3543 times)

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Offline cryptlabsTopic starter

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Help fix LED flicker
« on: November 22, 2015, 07:43:47 pm »
Hello,

I have an led strip 12v DC connected to a switching power supply which also runs my cnc machine. When the machine is on load the led flickers but not when the cnc is idle. How can i make the led stable?

Regards
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Offline max666

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Re: Help fix LED flicker
« Reply #1 on: November 23, 2015, 12:31:40 am »
Put in a diode and an electrolytic capacitor before the LED strip.

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Offline cryptlabsTopic starter

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Re: Help fix LED flicker
« Reply #2 on: November 23, 2015, 01:43:04 am »
Quote from: max666 on November 23, 2015, 12:31:40 am
Put in a diode and an electrolytic capacitor before the LED strip.


Thanks for the reply [emoji4]
What size and kind for the components?
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Offline cryptlabsTopic starter

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Re: Help fix LED flicker
« Reply #3 on: November 23, 2015, 01:52:37 am »
I tried a 1n4001 diode with a 450 microfarad capacitor but its not working.
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Online TheSteve

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Re: Help fix LED flicker
« Reply #4 on: November 23, 2015, 04:44:17 am »
The power supply is dropping voltage because of the load of the CNC - the proper solution is to get a second power supply just for the LED lights or get a power supply capable of more wattage to power both.
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Offline max666

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Re: Help fix LED flicker
« Reply #5 on: November 23, 2015, 11:28:14 am »
Quote from: cryptlabs on November 23, 2015, 01:52:37 am
I tried a 1n4001 diode with a 450 microfarad capacitor but its not working.

Well, without knowing any more detail about your LED strip, I would have gone with at least 10 times that capacity, if I had to guess.
If I do some very crude napkin math, and assume you have a 5 W @ 12 V LED strip. Then the current would be 0.4 A, so the load resistance the LED strip provides would be 29 Ohm. A 4500 µF cap and a 29 Ohm resistance have a time constant of 0.1 s (after that time the cap would be dischared to 37% assuming an ohmic load), so if we go for maybe a third of that we would be able to bridge a drop for about 0.04 s. I feel like that would be barely enough, so I guess you need at least 4500 µF for a 5 W @ 12 V LED strip. But then again I don't know how long your voltage dips out or how much power your LED strip has.

Or use a separate power supply like Steve suggested.
I hope you're not powering any logic from that 12 V power supply as well.
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Offline djQUAN

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Re: Help fix LED flicker
« Reply #6 on: November 23, 2015, 12:14:53 pm »
As we are working with little info here. Could be the wire going to the supply is dropping the voltage? How about running separate wires from the CNC and the LED strips going back to the supply?
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Offline cryptlabsTopic starter

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Re: Help fix LED flicker
« Reply #7 on: November 24, 2015, 04:21:50 am »
This is my led and power supply. The led needs 12v 105ma.
The power supply is rated at 12v 10A.


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