Protection against 230 Vac when input port should receive signal btw 0-24Vdc

Thread Starter


Joined Mar 19, 2016
Hello guys!

I need to design a protection circuit to avoid the destruction of a digital input port. This digital port should accept signals between 0Vdc and 24Vdc. However it is pretty easy to connect a power supply connector with 230 VAC to this input port because both connectors are very similar. Therefore to avoid this wrong connection i need to design an easy protection circuit with some LEDs in order to indicate to the user that the connection is wrong. Anyone has an idea about what component can i use?



Joined Jul 21, 2012
Don't use connectors that are very similar!

Change one to be completely different.
Even if you have to retrofit each & every unit in existence.

If you blow up a device,or a person,or start a fire,having a magic gadget that is supposed to warn people won't get you far in court!


Joined Oct 15, 2009
I second the change connectors..
Silly/Dangerous to use similar connectors in the first place.. Fix that big problem..