Quick questions about small WS2812B addressable LED string.

Thread Starter

Emehgee

Joined Aug 2, 2018
8
Hi there,

Working on a project that incorporates a small length of 5V addressable LEDS.

I've read its a good idea to include a capacitor across the 5V and ground before the LEDs.

I was wondering if a 470uF cap is big enough, I read that I should put 1000uF but I don't have that on hand and kind of wanted to get this project running.

Also, the LED string comes with two additional wires, an extra 5V and ground, I've heard them referred to as power injector wires.
Since I'll only be driving a small amount of LEDs and I got a supply that should have a good margin over what is required current-wise. I was considering just soldering the cap between these wires to make my life a tad easier. Do you think this will present any problems. Going to make sure they are connected to the main 5V and ground with my multimeter tomorrow.


Thanks!
 
Last edited:

dl324

Joined Mar 30, 2015
8,877
How much current are you drawing from the 5V supply?

How much current is it rated for?

Do you also have some ceramic decoupling caps?
 

Thread Starter

Emehgee

Joined Aug 2, 2018
8
How much current are you drawing from the 5V supply?

How much current is it rated for?

Do you also have some ceramic decoupling caps?
At most I'll be drawing 3A but more like 1.5-2.

If you're asking about the current rating on the supply it is rated for 10A.

I'm not certain if decoupling caps are a certain kind of capacitor, I have some very small ceramic caps that are 10nF and 100nF, all of my larger ones are electrolytic, the one I was thinking about using is rated for 25V.

Thanks
 

dl324

Joined Mar 30, 2015
8,877
How much current will the LEDs draw? If it's low, 1000uF is probably overkill; don't know where you're being told that 1000uF would be better than 470uF.

If the power lines to the LEDs are long, you'll get better mileage distributing the decoupling capacitance along the power line. This is how most logic boards are designed. Small ceramic caps are distributed among the IC's at some ratio that's not fixed. There might only be one electrolytic on a board, but numerous ceramic caps.
 
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