Resistor for LED is necesary ?

[Guitafuzz]

  Hi, I have a problem with the resistor that goes to the cathode of the LED, I'm using ultra bright LEDs  but when I put the resistance of 4.7 K, as shown in the wiring diagram the LED does not light so bright as when I place it directly with the battery.

 my question is necessary to place the resistance and what is the function of this resistance? Thanks in advance

[Comfort Player]

Yes the resistor is neccessary.  Without it you will blow the LED.  The purpose of the CLR resistor is to limit the amount of current going to the resistor, hence Current Limiting Resistor.   If the LED is to dim simply lower the value of the resistor.  Try 2k and see if that is more to your liking.

[TNblueshawk]

Wow, I have never had this issue with the water clears, quite the opposite. I know someone who goes as low as 820 ohms I think and the LED does not blow should you have to go that low.

[CRBMoA]

LED can vary ALOT!

As a rule, whenever I pull an LED out of my parts bin, I slap it on a 9V battery (that I test for proper voltage first) and use a 4K7 resistor. I look at it and decide if I want brighter and dimmer, and regardless of what the BOM says, I install what I want in the CLR position.

I have used everything from 1K5 to 6K8. It just depends on what I want to see, and what the actual LED does when I hit it with 9V.

[LaceSensor]

For the ultimate in pimp, use a 10 or 20k trim pot on a peice of vero and use that in place of the CLR.
Make sure you put some kinda small value CLR in series for if the trim pot is set to 0 ohms.

Nice little addition to any build.

[jolly1423]

I've been using 1k's on my water clears, no issues, super bright...

[DutchMF]

I've been using 1k's on my water clears, no issues, super bright...

Must hurt the eyes though..... No, seriously, try a number of different values for the CLR, and decide what you want/like.

Paul

[TNblueshawk]

I've been using 1k's on my water clears, no issues, super bright...

Must hurt the eyes though..... No, seriously, try a number of different values for the CLR, and decide what you want/like.

Paul

If you stare down into the middle of it, yes, you might go blind. I think if I gigged and had to deal with that situation of looking down a lot and switching in and out of things I would go with diffused anyway. But for the home hacker that I am I love the bright light! I like things that are shiny, bright and jingle  I'm such a neanderthal!

[jolly1423]

Yeah, I did experiment, I like 'em super bright

[bigmufffuzzwizz]

I've used many different values as a CLR for LED's. I've heard of people going up to 10k for superbrights cause they are sooo bright. Diffused are more practical for gigging, but the superbrights look so much cooler!