[sdiy] Protecting microcontroller inputs from - voltage?

[The Old Crow]

  Like this:

              470 ohm ~ 1K
 I/O pin]--+--/\/\----------< to whatever
          _|_
          /_\
           | anode
           |
          gnd

  The idea is to limit the diode current if the negative input voltage 
gets too large for the diode to clamp without burning out.

Crow
/**/

On Sun, 9 Nov 2003, Andre Majorel wrote:

> > small resistor in series with the I/O pin and whatever it is sensing.
> 
> On which side of the resistor would you put the diode ?