LED 6.3v tap

[ioginy]

Hey all.

I'm building a plexi cabinet for the amp I am working on and I want to install LED's to light up the front face plate. I figure I can hook the LEDs up to the 6.3v filiment tap, but I have a nagging feeling there is more to it than that. I know LEDs are diodes and will only allow current to flow in one direction. In my head it seems that I should be able to just hook them up, but I want to be sure before I do anything drastic.

Is there a correct way of using LEDs or can i just plug and play?

Thanks for everyones help.

[Geek]

Hi,

Red and green LED's are pretty tolerant. Just use a series rectifier diode (to save the peak reverse voltage of the LED) and a dropping resistor to limit the max. current.

Blue LED's need DC to live long.

Personally I like running superbright LED's at about 600uA.

Cheers!

[chrish]

Would this help you?

http://led.linear1.org/1led.wiz

[Dynaco6550]

LEDs simply placed across 60Hz AC will have a noticeable (and sometimes quite annoying) flicker.

I prefer to drive LEDs with a DC supply. You could probably even take it from the existing heater supply, all you will need is a rectifier diode and a capacitor, say 1000uF@10V (if using 6.3AC as the source supply).

That should give you nice steady LED light.

Good luck!

-Aaron

[Geek]

1000uF? That's too big for a LED. Typical rule-of-thumb for power supplies is 1000uF-per-amp.

I use (for my blue LED's) a 1N4007, a 10uF cap to ground right after it, then a dropping resistor. It all fits in some heatshrink and adds maybe 1" onto the LED and gives nice two-wire leads like any light bulb to the AC supply.

Cheers!

[ioginy]

Ugh, I knew it would be more complicated then I hoped. That dandy little calculator said I would need a 180 ohm resistor which makes perfect sense.

BUT, I am going to have to make a rectifier of sorts to get a DC current off my filament line. OK, that is doable, however, does anyone have a schematic for this. I am still learning how to make things from scratch, so I really like to see examples before I tie things together.

Thanks a heap!

edit-

I just had one of those click moments when re-reading your posts above. With the diode it would just make a half wave dc current. I get that now, however I don't understand what the capacitor is for.

[Geek]

Not hard to do



(you may want to use ~47uF for the regular LED though)

...however I don't understand what the capacitor is for.

To keep the flickering from driving you buggy and in the case of a blue LED, keep it alive.

Cheers!

[soundbrigade]

OR .... solder up a smallish SOLID STATE INTEGRATED CIRCUIT, a LM3915. It's a VU-meter IC and hook up the diodes so they somehow light up the plexi.

[Geek]

OR .... solder up a smallish SOLID STATE INTEGRATED CIRCUIT, a LM3915. It's a VU-meter IC and hook up the diodes so they somehow light up the plexi.

Almost an EE solution, Magnus.... but they would have used a PIC

Cheers!

[soundbrigade]

THIS (http://m.bareille.free.fr/vu-in13/vumeter_in13.htm) IS THE THING!!!!

[Geek]

Those are so cool!

[soundbrigade]

I've got two of them!!!

[ioginy]

that is cool! oddly enough, i am using the leds to light up the plexi a-la fiberoptically. I'm going to etch the control titles into the front plexi plate and when it powers up the LEDs will illuminate the etching. Should look pretty nifty.

Thanks for the tini-tiny rectifier (this is what I will call it from now on) layout. That will work great.

[nyazzip]

regarding "flicker", i thought all LEDs cycled on/off at 60hz, no?

[Geek]

No.