Re: [CAD_CAM_EDM_DRO] Re: Proper size of capacitors for transient suppression?

washcomp wrote:

>Except for the MPG leads (not yet installed), the longest distance of
>any line is less than 10 feet (3 meters). I used #18 wire for
>everything to keep the resistance to a minimum.
>
>The pendant also has the keyboard emulator embedded. I have heard of
>people connecting each terminal through a capacitor to ground (56
>terminals? Ee Gads!)
>
>

For digital lines, especially where you can't suppress the higher
frequencies
with a big capacitor, a real transient suppressor is the way to go. MOV
devices have very high capacitance, too. LittelFuse came out with a line
of devices that are sold through Digi-Key. I am using the SP720AB,
which Digi-Key sells under the order code of F2163. This is an SO-16
packaged device that protects up to 14 signal lines. The other 2 pins are
connected to ground and +5 V. Any signal outside the voltage on these
2 lines will be clamped to one of those supply rails. The capacitance is
very low.

Jon