Remote circuits (long wire) EMI, ESD protection

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Eh_Ba

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Hi
I have found this page about protecting micro's inputs from EMI, ESD.
https://www.digikey.com/us/en/techz...protecting-inputs-in-digital-electronics.html
These images are two ways to protect the sensitive component on the right (micro).

But what if we have a circuit with sensitive components instead of the switch on the left?
Do all or some of protection components on the right, help the circuit on the left?
Do we have to place a current limiting resistor and a zener diode and clipping diodes and ... in the left circuit or not?

If the both ends of the wire need special hardware to prevent EMI?

What about GND and Vcc?


Thanks
 

You have to place protection on both sides of long wire.
For VCC use larger capacitor and TVS diode. Do not use any series resistor. Additionally You can use ferrite choke also on signal lines.
 
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    Eh_Ba

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Thank you GUMY.

Do I have to use ferrite on both sides too?
Is there any definition for long wire?
And what about the shielded wires?
 

Yes, use ferrite beads on both sides.
Wire lenght which could cause problems, depends on enviroment (how "noisy" it is), cable type and signal type. For TTL signal on flat cable 1m is long, for RS485 signal in shielded cable 100m is long. But don't take this lenghts as a rule..
Shielded cable helps.
 
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