There's a story from a couple of years ago I still remember, for some reason.

Anna has a relative who's a Physics guy, dealing with lots of different Electricity issues. He's also a "big mouth" - a boaster, "my way or the high way" kind of guy.

Well, we were together at some family gathering, and people started talking about how bad the education of sciences is (people like talking about these issues...), and he, trying to prove it, asked me: "You're an EE, do you know what cos(phi) is ?". He didn't mean a cosine of some random angle phi, of course, he meant something specific. I said I don't know exactly, I only know it's from the AC electricity world. He rode on his success, claiming that a well educated EE should know this.

I didn't react at the time, but it hurt me quite a bit. I know lots of things about other EE topics - mostly the low-voltage ones. I never worked/dealed with high power applications, hence I don't know all the definitions from there exactly. No one can know "all of it", people must specialize in some way, and I believe that I "know my stuff" in topics I actually work with.

Well, now I know exactly what cos(phi) is. As I mentioned a few days ago, I "came back to the roots" by doing some research dealing with voltage stability controllers, and as a part of it I'm reading a lot of stuff about power, AC circuits, transmission systems, etc. So, I learned what cos(phi) is.

If you're interested: cos(phi) denotes the load power factor, namely the ratio between true (active) power and apparent (total) power: P/S. phi in this context is the phase difference between the voltage supplied at the load and the voltage coming from the AC generator.