[TowerTalk] 12V transient/noise filtering?

[Lux, Jim]

On 5/13/21 10:42 AM, Jim Brown wrote:
> On 5/12/2021 7:39 PM, Michael Tope wrote:
>> You would have to dive into the EMI/EMC specs provided in the 
>> datasheet - in particular conducted susceptibility
>
> In my experience, most EMI is common mode, and is not accurately 
> described on data sheets. 


but here, I'm not looking at EMI - I'm concerned about differential mode 
transients (inductive things like relay coils, etc.) blowing up the 
other things in the circuit.  Things like having a USB interface - they 
tend not to like big transients, and I'd rather not blow up the laptop, 
or Raspberry Pi, etc.  Sure, they have some sort of voltage regulator 
that brings 12V down to 3.3 or 5V, but things like the venerable 7805 
have a 35V absolute max so that 50V transient will kill it.

A DC/DC converter like those from CUI might have a wide range input, but 
probably not 50V and they have no reverse protection.


Something like a reverse biased 20V Zener might actually solve my problems.