Indeed, but as Roland posted later today, there's a 2.7k resistor
on each of the darlington's inputs in the ULN2803, and that's
why I chose that chip.

Here's a question though: the code places TRISA and TRISB as I recall,
which causes the output pins to have high impedence off state to my
understanding; so, "collector-emmitter" current from the darlingtons
wouldn't be pushing into the off-state PIC output pins, right?
I hope that question made sense, but forgive my complete lack of
recollection of transistor operation. :(

Thanks,

Gustaf

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Francisco J. A. Ares
> Sent: Friday, February 27, 2004 6:34 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE:] Release of magic smoke
>
>
> Gustaf J. Barkstrom wrote:
>
> >Note also that I
> >am not using a resistor between the PIC output pins and the
> Darlington array
> >input pins.
> >
> >
> >
> >
> This may be the problem, PIC output pin logic low level is close to 0,
> so this is ok, but the logic high is 5V (for a critical example) and VBE
> is close to 1V on darlingtons.
>
> Hope this helps
> Francisco
>
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