Metal Oxide Varister

Metal Oxide Varister FARM SHOP Handy Hints Jerry Smith Ionia County Mich : Like many of your subscribers in rural areas I have suffered through a power outage or two A few years ago several of my appliances were damaged by a voltage surge Trying to fix them myself I learned about a common electronic component called an M O V metal oxide varister These are usually a small blue or green disk with two wires soldered to the circuit board They are in practically every modern appliance for surge protection They are usually soldered in near the power supply of a circuit board just after the fuse and connect from line voltage to the ground At line voltage no electricity goes through the M O V but at higher voltage almost all the electricity goes through to ground and blows a fuse on the circuit board Often you can visually spot a blackened crack in the M O V The M O V isn t necessary for the component to work so if you find a damaged M O V cut it out Then replace any blown fuses and try to turn the appliance on If it works the M O V was the problem Then go to your local electronics supply store and buy a new one to solder in to replace the old one I have replaced several at about $2 each

To read the rest of this story, download this issue below or click here to register with your account number.