Hi: I have wired in a fan and want to control my feedback. I know a lot of people will tell me to wire in a relay which I could do easily but want to learn a little about diodes hence this blog. I have a 120W fan that operates off of 12V. What rating of diode should I get? I was just at frys (local electronic store) and bought one that had a V rating of 40, forgot the amp rating but it was plenty. Anyways, I monitored diode and did work but noticed that it did get very hot to the touch. I continued to monitor it for about 30-45 minutes. Never burnt up but did get very hot to the touch. How do I determine what size I need? Again my load is 120W with a push of 12V making the load (I think) of 10A.