Hi all,

Quick question here.

  http://www.pacificsun.ca/~john/ELS/photos/IO_Circuit.jpg

The link to the above circuit shows how I plan on changing the
Electronic Lead Screw circuit to protect the processor inputs from
transients.  I can see someone accidentally putting 12V onto an input
pin with switch that should close to ground instead closing to 12V.

The circuit using R45 and R43 limit the current through the diode but a
spike might still trash the processor.

The circuit using R44 and R46 forces the power supply to absorb the
input and perhaps can trash the diode with excess current but R46 limits
the current into the processor.

Suggestions or alternatives?

Thanks

John Dammeyer


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