U better PWM drive the LED. It will be good for the LED

 

yes, if you have a circuit for 12V -> 11V @ 1 Amps?

I have here DPAK p-ch MOSFETs for instance.

But I am not very familiar with these kind of circuits.

PIC micro is no problem to use.

 

u are way too confusing.

 

hey if you say you bought it from a vendor.. they have a website? most people do..
lets see a link?

 

http://www.ebay.com/itm/1pcs-10w-High-Power-Square-Pure-White-Led-700-800LM-/110762839389

Not from this seller.
Not from eBay.

Nearly as common as a light bulb in a supermarket.

Look I appreciate your replies.

The problem is the diode (NOT THE LED), getting hot.
I search for a better solution.
Not a power resistor.

And it's way over my head to try to tinker with it install something else and make it even worse.

I would also appreciate if you have a concrete circuit for 12V -> 11V.

If that's confusin etc., it't not urgent, I use it in the night for the computer to see the keys, and this works, I don't care about the 140C diode, the computer server case is open atm.

Can you follow I want to close it at some time, and don't want trouble from the diode, melting cables etc.?

If I install a TO220 diode on the cooler sink, this won't drop 1V I guess, so I don't even think about trying this.

Or some kind of CFL coil that has 2 Ohms resistance, and can distribute the heat due to it's mass? I have 20 or so here to try.

Maybe I will just tie the diode into the airflow of the cooler, problem solved!

 

I had to salute the OP.

OP insists on using a diode.

Or is the OP too dumb or too lazy to read about LED's with current limiting resistors.

He has to use a diode and not listen to us.

I'm outa here for good.

 

U can use one from this

 

My last word on this too.

Use a 1.2 to 1.5 ohm 5 watt resistor. You do not need to stock pile them, just buy 1. Do not use a diode, it is not the right thing to use.

 

OK thank you for your input.

If I use a MOSFET in linear mode (effectively dropping voltage, equivalent to a resistor), that's also a semiconductor junction.

And this is well used in circuits.

The only difference MOSFET/diode: diode isn't adjustable (no gate).

I would like to build it using a MOSFET, but they are expensive too.
I have many of these around on behalf of a third party, but only few in my own inventory...

The diode is from a defective CFL board...

My problem goes more into the direction how to cool such a small diode properly, and how to attach it to the cooling grid properly.

I have not yet found any good solutions how to do this.

Well...

I could use a TO220 diode from a voltage converter, it has shortened, one half, the other half still intact. Zero cost, otherwise junk part. And can be mounted on the heatsink. But maybe, only will drop about 0.4 to 0.5 volts.

So the small standard diode is good because it drops about 1V.

Power resistors I also have many around here, 0.1 Ohm, 0.27 Ohm.

Mechanically, maybe I could wrap some kind of metal lug or clip around the diode, and screw it to a small cooling grid.

 

No more help to stubborn posters.

Mod's close this thread if the OP is refusing to listen to us.

 

No more help to stubborn posters.

Mod's close this thread if the OP is refusing to listen to us.

You seem only to reply here to boost your ego, and you expect nodding up and down. This is common on some forums. It's the Zuckerberg syndrome, you either agree to him w/o discussion, or you are fired.

Look I can find answers "Use a 2 Ohms resistor" myself.

If I were you, and never used a power LED myself, I would not reply at all.

Finding an appreciate metal lug + wrap it + mount it on the cooler, why don't you try to help me with that?

 

This is common on some forums.

This Ain't just a forum for ur info....U will find more answers here than any other forum..And I am proud to be here. As the rest of the members.

So listen to us.
And stop wasting our time and listen to the given advice.

I think u have the ego to not to listen to professionals.

No one here agrees to use a power led in series with a diode unless it's an AC source. And u have it easy. A regulated 12V with plenty of power. So why the freakin diode thing

We cannot waste time, there are others who need help.

Look via thread and read it.

U don't need a heat sink to mount a resistor. Use a at 1amp u need 1 ohm to drop 1V. Power is 1W and u can get 2 W and it will stay cool enuf to touch at free air.
If u are afraid tht it will heat up get 5W , it will last longer than ur LED.

 

Ok, so I have used a power LED.

With the circuit you have provided, I would use a RESISTOR

A diode is not required, as the LED provides that function.
Unless of course you are worried about some form of back-EMF possibly caused by the fan (but you don't state this).

The only reason I could see why you would want to use a silicon based solution rather than a resistor (a resistor of course being the correct solution to the circuit and the question that has been posed), would be if you wanted to control the power that is going through the LED, which in this case a MOSFET would be the correct answer, not a diode.
But you haven't asked to control the power through the LED, only to reduce the voltage or the current, so the answer is of course a resistor.
I believe that R!f@@ might have already provided the correct answer for the type of resistor for you.

 

OK thank you for your input..

Ur welcome

You seem only to reply here to boost your ego, and you expect nodding up and down. ?

U see my posts as EGO post ? My my..u are really good at defining people.

It's the Zuckerberg syndrome,

WTF is tht ?

Look I can find answers "Use a 2 Ohms resistor" myself.

Do u know Ω Law ?

If I were you, and never used a power LED myself, I would not reply at all.

U think u know me? I have used Led's up to 100W in all kinds of projects.
U are just stuck with a measly 10W.

Finding an appreciate metal lug + wrap it + mount it on the cooler, why don't you try to help me with that?

U don't need help with that. You have already done it or you just said how to do it.

 

Gentleman, this will stop. R!f@@, this is a no flame zone, please remember that. If you don't like what the OP is doing just move on.

I have used LEDs, both power and not. I left because I could not get the basic information needed to be of any assistance. Since I could not help, and don't need the aggravation, I left. R!f@@, you need to do the same.

There is no such thing as a 12V LED. There are modules that have a resistor included, or have multiple LEDs. A LED must have a current limiting resistor, you are using something else if it is described as a 12V LED.

LEDs are basically simple, they do not limit current, they will burn up if attached to a power supply by themselves. The big differences between power LEDs and regular LEDs is the heatsink and current. The increased current causes a much greater variation in Vf, something I mentioned earlier.

When talking about a module (which is not the same as a LED, even if it has LEDs included) the rules do change. This is why spec sheets are so important.

The tutorial I wrote for LEDs mostly applies for all LEDs.

LEDs, 555s, Flashers, and Light Chasers

I am talking about the first two chapters only.

I have used LEDs as low voltage zener diodes, but this application is seriously flawed. If you need to control voltage you need a voltage or current regulator, not a LED module.

That is basically all I have to say on the subject.

 

Sorry bill. I'm leaving.

 

R!f@@

Pls. accept my apologies.
You have used power LED, yes I agree.

Currently I will treat this thread as not processable for advice/assistance.

I have also not visited for two days.