I'd go to the local library and look in the 600 area (Dewey Decimal
System) for electronics books.  The amateur radio related books are a good
starting place.  If you're near a university, check out their library for
more involved texts.  Then you'll have a better idea of what you're
looking for.  Electronics covers a lot of territory today and no single
book has it all.

_______________________________________________________________________
 Lynn Richardson          | lrich@qni.com    |Progress Instrument, Inc.|
 Design Engineer          | wa0znl.ampr.org  |807 NW Commerce Drive    |
 Circuit Design DC to 1GHz|  [44.46.176.3]   |Lee's Summit, MO 64086   |
 Asm 6805, Z8, 8051, PIC  |                  |Phone: (816) 524-4442    |
 C                        |                  |Fax: (816) 246-4556      |

On Mon, 23 Dec 1996, Brian Scearce wrote:

> I hate to make my first post to this list a classic rookie question,
> but I really want to get working on my project over the Christmas
> break.
>
> I have eight banks of eight LEDs arranged in a common cathode array.
> My original plan was to use a 74HC138 as a bank select, and wire PORTB
> to the anodes through current-limiting resistors.
>
> The 74HC138 can only sink ~25mA, so I was planning on presenting only
> one bit at a time on PORTB.  I did some more calculations, and I find
> that this approach will be too slow.
>
> So, I want to be able to sink more current (20mA/LED * 8LED = 160mA).
> This is where I start to get out of my depth.  I'm thinking eight PNP
> transistors (2907?) with the bases attached to the 74HC138 outputs, the
> emitters attached to the banks' cathodes, and the collectors grounded.
> But I don't know if I need current limiters between the transistors and
> the 138.  I don't know if I've chosen the right transistor for the
> job.  I don't know if the information presented in, say, the Digi-Key
> catalog is enough for me to pick the right transistor, or if I need a
> data book.  I don't know which data book covers these parts.
>
> I'm not describing my problem in order to have someone present me with
> a solution, just to describe my level of expertise.  The sci.electronics
> FAQ recommends _The Art Of Electronics_ (2nd ed), by Horowitz and
> Hill.  Is this a good book for someone at my level?
>