[sdiy] DC blocking caps on inputs - or not?

[Rick Jansen]

You can always use a buffer opamp as an input, with proper diode protection. For external inputs I like that as a safety precaution too, if the chip is an expensive one.

> On 06 Feb 2016, at 17:30, Tim Ressel <timr at circuitabbey.com> wrote:
> 
> Two things. First, some circuits need blocking caps because the chips input pin has a DC bias on it. Second, if you want to protect from fast transients on the input, use a 100pF cap to ground after the input resistor. This will take care of most hits including ESD.