Floating Computer

[Yevgenip]

Hi.
I want to make my computer look like it is floating by putting some Ultrabright LEDs under it (Like in those fancy cars).
I figured I'll use the transformer fan output which is 12 V as a power supply, pass it through a voltage devider and then connect the LEDs in parallel.

The LEDs work on 3.5 Volts and 20 mA.

Two Questions:
1) Will my design work? have a better design?
2) What is the maximum ouput power my fan output can produce? /or/ What do I do if I don't want to burn my PSU?

Thanks.

 

[ante1]

Hi Yevgeni,

You need series resistors for the LED:s and you can feed them from the PC PSU on the 5V or on the 12V output. These outputs can provide power enough for hundreds of LED:s. It won

 

[Yevgenip]

Thanks, Ante. 8)
I know how to calculate the resistance I need to get the needed current and voltage drop. Do you mean to connect a resistor to each LED or a really big one before the parallel junction? Did you mean a different calculation?

Thanks.

 

[Yevgenip]

Oh and another thing:
What kind of fuse would you recommend? How do I calculate the amps of the fuse? where to put it (On the circuit that is)?

Sorry for all the basic question, I realy don't want to screw it up and plus: You are an electronics theory expert god 8), and I'm just hopping to a Jr. theorist. :'( ;D

 

[surajbarkale]

As you have voltage accross LED's 3.5V you can connect 3 of them in series & then parallel sections of three series LED's. This will reduce the value & power loss in the series resistor.

 

[Yevgenip]

Good idea, thanks. ;D

 

[ante1]

Yevgeni,

While you are calculating the series resistors you also know the currents so just sum them up and add some headroom and you have the value of a suitable fuse. Put it in the positive feed line close to the source.

 

[Yevgenip]

Thanks Ante, useful info.

P.S.
I can't see your personal picture. ???

 

[Yevgenip]

Oops, Sorry. ;D
I can see it now.

Here is something nice for you: www.myquickmail.com

 

[ante1]

I wouldn

 

[Yevgenip]

Why not, have you tryed it?

 

[ante1]

Yes, and I was re-routed to some other site with lots of trouble. The

 

[Yevgenip]

Wow, thanks for the warning. I wasn't redirected anywhere, but I think I'll stop using it. Even though someone told me he is currently using it. ???