Re: gEDA-user: Laser diode operation?

[Kipton Moravec <kip@xxxxxxxxxx>]

I would not say never want to parallel LEDs.

The example is what if you do not have enough voltage to go series?

What if you need to operate if one LED blows? In Series if one goes they
all go. 

Most large arrays have LEDs in series and in parallel. 

Like a 5x5 matrix for example (5 in parallel connected in series to the
next 5 in parallel, etc.) the LEDs are connected together by row and by
column. Zener diodes are added to help take up the current if too many
LEDs go out in the parallel part.  

In Bob's case I would probably put 5 in parallel in series with 5 in
parallel and have a 5 x 2 matrix.

Kip

On Sat, 2008-08-30 at 09:58 -0700, Larry Doolittle wrote:
> Guys -
> 
> On Sat, Aug 30, 2008 at 07:38:06AM -0400, Bob Paddock wrote:
> > On Friday 29 August 2008 11:15:03 pm Robert Butts wrote:
> > > I'm using ten [laser diodes in] parallel.  I WAS going to
> > > just use a 1 amp 5 vdc power supply with a 2.8 V zener diode
> > > to adjust the voltage to 2.2 V. 
> >
> > Does not have to be complicated, but you never want
> > to parallel LEDs/LASER Diodes as they are a current
> > driven device.
> 
> Right.  The traditional and easy way to get a bunch of LEDs
> (or equivalent) to light up equally is to put them in _series_.
> Then you only need _one_ current limiting resistor (or fancier
> circuit).  Can you trade in your 5V supply for a 24V supply?
> 
>    - Larry
> 
> 
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-- 
Kipton Moravec AE5IB
"Always do right; this will gratify some people and astonish the rest."
--Mark Twain




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