I am building a small handheld tester for pixels using a nano, and I want the output to be fault-tolerant, so that if the pixel input is shorted to ground or +12v, it will not damage the tester. So I am looking for a simple little buffer circuit to connect between the nano’s output pin and the test lead going to the [possibly shorted] pixel. Suggestions?
(Alas, google and bing searches have failed me. No matter what other keywords I use and no matter how specific I get, neither search engine is giving me relevant results. They focus too much on the “fault tolerant” part and I am flooded with other results for protocols and software. Closest I could fine was fault-tolerant RS-485.)