[hpsdr] Starting BOM already

[Philip Covington]

Chris,

I looked through my notes:

Use this LED:

Digikey P/N: 160-1421-1-ND

Lite-On LED ALGAAS RED THIN 0805 SMD, LTST-C171CKT

$0.15 each qty 1

Use a 1k resistor for the 3.3V LED, 1.8k for the 5V LEDs, and 2.2k for
the 12V LEDs.  Those values give equal brightness for the above LED.
10% tolerance resistors are fine.

73 de Phil N8VB

On 3/13/06, Christopher T. Day <CTDay at lbl.gov> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
>
>
>
> Ok, I'm lost. Here is the Kingbright LED datasheet, which is typical of most
> of the SMT LEDs I found on Mouser.
>
>
>
> http://www.hamsdr.com/personaldirectory.aspx?id=156
>
>
>
> Here is the Vishay LED datasheet at an order of magnitude less current.
>
>
>
> <http://www.hamsdr.com/personaldirectory.aspx?id=155 >
>
>
>
> The way I would read these intensity values, they are about 1/1000 the
> values you are talking about.
>
>
>
> Clearly, I have no idea what I'm doing here and await enlightenment.
>
>
>
>
>
>             Chris – AE6VK
>
>
>
>
>
>  ________________________________
>
>
> From: KD5NWA [mailto:kd5nwa at cox.net]
>  Sent: Monday, March 13, 2006 4:00 PM
>  To: Christopher T. Day
>  Subject: RE: [hpsdr] Starting BOM already
>
>
>
> They must be horribly inefficient LEDs. It should be more like 1ma to 2ma
> for a modern diode.
>
>  You also might want to consider the light output of the LED, for a status
> light inside a piece of equipment you can run it at less current that the
> specified for full output. 3,000 to 12,000 millicandelas will be annoying as
> heck if you look at it straight on.
>
>
>  At 05:43 PM 3/13/2006, you wrote:
>
>
>
> Ok, guys, we – or at least I – have a problem here. All the 0805 SMT LEDs I
> see in Mouser have an operating point of 20mA. At 12V, I make that out to be
> 0.24W into the dropping resistor. All the 0805 resistors I can find are
> limited to 1/8 or 1/10W => they won't last very long. The Vishay TLMC3100
> that I'd picked originally has an operating point of only 2mA, but is
> packaged in PLCC-2 form, which is about twice the size of 0805 (unless I mix
> up my metric and English and miss Mars) – go figure. Any chance of making
> the LED pads PLCC-2 and going with the original choice, or is it too late
> for that?
>
>
>              Chris – AE6VK
>
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at hpsdr.org
> Subscription help:
> http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
> HPSDR web page: http://hpsdr.org
> Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>
>

 1142300792.0