How to dim a power LED

Phil2008 · 7 Sep 2016 at 20:37

I have the Cooltek W2 case and I haven't got the power LED connected at the moment but I would like it connected. But with it being in my bedroom and having the pc on a lot when Im sleeping, the LED is just too bright.

I had one idea, would a 7V Voltage Reduction fan cable make the LED any dimmer?

metalmackey · 7 Sep 2016 at 21:07

Shut ya eyes or bung a bit of blue tac over it before you go bed.

.Ox. · 7 Sep 2016 at 21:12

I bought some 'LightDims' for my room. Little stick on dots which go over LED's and come in different sizes. They do different colours, and have ones which block out 80% of the light or completely opaque. £5 from the rainforest, bit much for what it is, but i couldn't be bothered to mess about.

I'm using the 80% ones and they're awesome.

Tealc · 7 Sep 2016 at 21:31

A resistor will do it. There'll be two wires going to the led. Break one of the wires and shove said resistor between the two broken ends. Solder or twist and bung some tape on.

Choice of resistor depends how dim you want it. 1k would be my choice as a starting point. Or use a 5k trimmer potentiometer and dial in your preferred illumination.

Alternatively you could make an extension cable and wire in the resistor/potentiometer so as not to break your original cable.

With mine I also changed the led colour and when doing so added a small resistor at that point. Thr original blue was enough to light my room. Now it is just indicator bright. Subtle.

Phil2008 · 7 Sep 2016 at 22:49

.Ox. said:
I bought some 'LightDims' for my room. Little stick on dots which go over LED's and come in different sizes. They do different colours, and have ones which block out 80% of the light or completely opaque. £5 from the rainforest, bit much for what it is, but i couldn't be bothered to mess about.

I'm using the 80% ones and they're awesome.

That might be hard to do with my case because the LED shines around the power button, so I would need it stuck onto the LED. I haven't even bothered connecting mine up at all yet, because from pics in reviews the LED lights everything up, not just the power button......

Phil2008 · 8 Sep 2016 at 12:30

I have just looked and theres 1 LED either side of the power button, no wonder its so bright. So Im thinking I will have to use a resistor, but what am I buying as this is unknown territory now? I see I can buy like 50 or so for a few ££s on the bay, so Im guessing I want a pack that goes up in stages, but no idea?....

http://www.ebay.co.uk/sch/i.html?_f...TRC1.A0.H1.Xresi.TRS0&_nkw=resistors&_sacat=0

Tealc · 8 Sep 2016 at 13:48

If you buy 1k, a pack of 100 for £1 then if they are too bright with 1 you can put 2 in series for 2k, if they are too dim with 1 then you can put 2 in parallel for 500ohm, or multiples.

If you could measure the current and voltage with a multimeter you could determine this before buying.

Phil2008 · 8 Sep 2016 at 14:19

So Im guessing 1k is 1000 and the higher the number the higher the resistance?

ov_sjo · 8 Sep 2016 at 14:21

A suitably coloured pen.

tom_e · 8 Sep 2016 at 14:24

Phil2008 said:
So Im guessing 1k is 1000 and the higher the number the higher the resistance?

Correct.

Phil2008 · 8 Sep 2016 at 14:34

So I will order the 1k ones and then you guys can let me know what resistor I need depending on the brightness the 1k gives out.

I am guessing its ok to cut the metal wires to make them shorter?

Phil2008 · 8 Sep 2016 at 14:42

ok I bought "Carbon Film Resistors 1/4W 0.25W" 1k Ohm. pack of 20.. Are these correct? http://www.ebay.co.uk/itm/152059712...49&var=451259792618&ssPageName=STRK:MEBIDX:IT

Phil2008 · 8 Sep 2016 at 15:13

Tealc said:
If you buy 1k, a pack of 100 for £1 then if they are too bright with 1 you can put 2 in series for 2k, if they are too dim with 1 then you can put 2 in parallel for 500ohm, or multiples.

So if I connect the resistors on the + lead, it will dim the LED's and if I put them on the - lead it will brighten then LED's. Is that what you mean by saying "series" and "parallel"? Sorry this is all new to me.

C64 · 8 Sep 2016 at 15:15

marker pen works well I coloured in the the back of my akasa eclipse led

tom_e · 8 Sep 2016 at 15:17

Phil2008 said:
So if I connect the resistors on the + lead, it will dim the LED's and if I put them on the - lead it will brighten then LED's. Is that what you mean by saying "series" and "parallel"? Sorry this is all new to me.

No, in series means you cut one of the wires going into the led and put the resistor between the 2 cut ends.

Parallel means you fit the resister across the + and - wires.

http://www.bbc.co.uk/bitesize/ks3/s...y_forces/electric_current_voltage/revision/4/

Tealc · 8 Sep 2016 at 15:35

No. When I say putting in series and parallel I mean with each other not as to create a new load.

Start by breaking the wire, any will do. Then strip both ends and put one resistor and attach a stripped end to each leg of the resistor. Now the current must pass through the resistor before it gets to your LEDs.

If the LEDs are too dim then get another resistor and sit it on top of the first and attach it by twisting legs over the first. The current is now shared across two resistors and the resistance is lower, therefore a brighter led results.

For a dimmer led you'd have two resistors in a row so the current must pass first through one resistor and then the other. This doubles the resistance and makes the led dimmer. Technically you could out them anywhere in the circuit and break multiple points but that's just messy.

Hope that helps.

Finners · 8 Sep 2016 at 15:40

Are you using the built in fan controller? If not you have a nice switchable 5v power right there and waiting. Would give you the option of 5v/12v or off

Phil2008 · 8 Sep 2016 at 15:47

Tealc said:
No. When I say putting in series and parallel I mean with each other not as to create a new load.

Start by breaking the wire, any will do. Then strip both ends and put one resistor and attach a stripped end to each leg of the resistor. Now the current must pass through the resistor before it gets to your LEDs.

If the LEDs are too dim then get another resistor and sit it on top of the first and attach it by twisting legs over the first. The current is now shared across two resistors and the resistance is lower, therefore a brighter led results.

For a dimmer led you'd have two resistors in a row so the current must pass first through one resistor and then the other. This doubles the resistance and makes the led dimmer. Technically you could out them anywhere in the circuit and break multiple points but that's just messy.

Hope that helps.

Yeah that makes sense, thanks.

Finners said:
Are you using the built in fan controller? If not you have a nice switchable 5v power right there and waiting. Would give you the option of 5v/12v or off

I am using the fan controller and its 7volt and 12volt, but I have got a 7V Voltage Reduction fan cable that I could try?

Finners · 8 Sep 2016 at 16:13

Is it 7v? Molex has 12v and 5v cables so assumed it switched between 12 and 5v

Phil2008 · 8 Sep 2016 at 16:19

The fan controller on the case uses a sata power connection for its power. on the switch at the rear of the case it says "7v, off, 12v"