[sdiy] Protecting microcontroller inputs from - voltage?

[Andre Majorel]

On 2003-11-08 22:07 -0500, The Old Crow wrote:
> On Sat, 8 Nov 2003, Bret Truchan wrote:
>
> > Question #2: What's the easiest way to clip out negative voltages?
> 
>   Use a diode clamp.  That is, a diode from the I/O pin to ground, with 
> the cathode on the I/O pin.  Check the microcontroller electrical spec, 
> but most will tolerate -1V or so.  If even less drop is needed, use a 
> Schottky diode.  In practice, a 1N4148 will work fine.  Caveat: put a 
> 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 ?
  
-- 
André Majorel <amajorel at teaser.fr>
http://www.teaser.fr/~amajorel/