I am considering building an AC protection circuit using the following schematics. I am a physicist and have little practical experience with implementation of electric circuits. Looking forward to your input on it.
- The 5A fuse is obviously for overload protection. (Even 1A may be acceptable. I put 5A for transients.)
- The ten 33V Zener diodes will not trigger till 330V (plus some forward voltage) which is higher than the AC peak. However, if due to some reason the AC voltage spikes the Zeners will trigger and blow up the fuse and ensure voltage remains the within the safe limit at output.
- The capacitors are there to filter DC from AC. (A power transformer and some other things up in the line.) I added some high resistance bleeder resistors. However their necessity seems to be debated on this forum.
My reason for using Zeners instead of varistors is that I will only need to reset the fuse in case a fault occurs. I am concerned if the Zeners will be able to handle the surge, and I haven't seen such implementation anywhere giving rise to lack of confidence. Maybe I am missing something? This is a hobby DIY project, so keeping cost down for mass production is not a priority. Please give your input on the circuit before I put it to test.