Maixium voltage on a input pin

[Acetronics2]

Hi, Robert

I think we mixed DIGITAL and ANALOG inputs ...

here you want 0 > 12 v to be 0 > 5 v !!!

so, you need a voltage DIVIDER ...

see Darrel's site for such an application :

http://www.pbpgroup.com/modules/wfse...p?articleid=25

Everything explained ...

Alain

[Demon]

Hi, Robert

I think we mixed DIGITAL and ANALOG inputs ...

here you want 0 > 12 v to be 0 > 5 v !!!

so, you need a voltage DIVIDER ...

see Darrel's site for such an application :

http://www.pbpgroup.com/modules/wfse...p?articleid=25

Everything explained ...

Alain

Yup, the signals from the sensors will be analog. Interesting tool, I added it to my favourites. There is a comment at the bottom of that page that puzzles me though:

"Do not use the Zener diode (D1) for analog circuits. It will adversely affect the readings.
It can be useful for protection of Digital Inputs though."

So, since I've lowered the voltage to an acceptable level for the PIC, then there should not be any need for extra clamping diodes, no?

[Acetronics2]

So, since I've lowered the voltage to an acceptable level for the PIC, then there should not be any need for extra clamping diodes, no?

It's an automotive environment ( remember the 45v ??? ) ... use clamping diodes instead of the Zener ... they won't disturb the divider.

Alain

[mackrackit]

In post #19 and #28 of this thread http://www.picbasic.co.uk/forum/show...ighlight=zener
Melanie talks about the zener.