I had two power supplies blow.. my computer would keep restarting as I get like 10-20 brown outs a day.. UPS = golden fix. Gotta keep that power smooth!!!
If you are going to uses a UPS is MUST be what is called a on-line UPS. Less efficient as they are always 'on' changing AC>DC>AC but there is zero transfer time. For several of my S4's and S2's I use http://www.cyberpowersystems.com/products/ups-systems/smart-app-ups/paragon-series/ol2200rtxl2u.html Pricey? Yes. However, are rock-solid.
btw, the s2's & 4's are the only ones on UPS's. When spiked (well, dipped really) they can be (are) the most susceptible to the sd card getting munged.. S3's and s5's just hang so the majority of the farm is not on UPS's. Waayyy too expensive to do that.
Very solid point, it has to use transistors or the switching time is just WAY to long.
I needed one for my computer lol. It kept kicking it and the miner offline so I got two, one for the comp one for the miner. It's an S3.