Guido, A life time ago, my hobby was electronics. I built voltmeters, scopes, radio, color TV, most of which have a power supply of some kind. Back in the day, people repaired TV's. Today you can't get parts cheap enough to repair most electronic devices. Not to mention even if you could, you couldn't solder them to the printed circuits.
As a kid I helped my dad built 3 phase converts. Some converters were static, capacitors only and some converters were dynamic, using capacitors and a second 3 phase motor.
My dad also a heating and air mechanic. Learned a lot growing up on the farm. Learned I didn't want to milk cows for the rest of my life.
Been retired 9 years and I still find it handy to know something about how things are made, how they work, especially electronics.
I have a life time collection of used diodes, capacitors, resistors, relays, switches, a real pack-rat. George