@Gary P posted:Thank you Vernon, I appreciate your honest comments and better solution. I run conventional off a transformer so I don't have to worry about compromising any DCS signal. I thought it was a starting point to try to come up with something that would work and not have to crawl around and check every TVS, I honestly didn't think the resistor and LED could handle the power but hadn't thought of using a regular 18V light bulb and fuse circuit. Thanks!
No problem, I had this idea in my mind for a while of this fuse and light indicator, but never previously shared with the forum.
Again, this is not my first choice. Best protection is the TVS as shortest and nearest direct path across the rails. This circuit represents a compromise, where it provides protection, and in the event of catastrophic failure provides a way for the fuse to blow and an indicator that could be seen remotely.
The other experts may chime in and shoot holes into my idea.
