What are fuses used for?


I have, I’m sure to many, a very dumb question. I keep reading about fuses.  I have a fairly sophisticated system and have never come across the need for a fuse.
Can someone tell me where these fuses go and what they’re used for?
128x128rvpiano
What I glean from your post is that fourth grade was a watershed year in your development. 👦
@ geoffkait1

I worked with several Acoustical Engineers (some PhDs) in the past, their coursework all expanded on Mechanical Engineering as this is how acoustics is best modeled. Just a plain old BSEE here.
Oh, they got their PhD in two years? Wow! They must have very large heads.