Personally I think ATX power supplies and DVD drives are pretty great for parts.
ATX PSUs contain transformers and inductors which can be used for wire salvage (not to mention the thing's actual wires). There's plenty of capacitors, resistors, and voltage regulators depending on where you look.
DVD drives contain stepper motors, DC motors, potentiometers, LEDs, and powerful lasers. (Powerful enough to delete your eyeballs in nanoseconds. Be careful.)
I've sort of given up salvaging parts. I have decades worth of salvaged parts (from equipment, from surplus, free samples, show giveaways, stuff from dumpsters where work threw out brand new or slightly used parts, from ebay and surplus dealer sales that I thought were too good to pass up, etc...)
And now I have piles of largely obsolete parts that are unlikely to be used, require special tools and programmers that are nearly unavailable, have unpopular values, and can't be obtained if anyone wanted to duplicate my project, or if I wanted to build them in bulk. 27C512 EPROMS. 4bit microcontrollers. ATmega48 microcontrollers (cause that was "big memory" back then.) 8kbyte and 2kbyte static RAM chips. (shucks. 1kbit static RAM chips!) CPLDS, FPGAs, SIMS, and DIMMS in at least half-a-dozen obsolete styles. Stuff that was discontinued, from companies that don't exist any more.
Further, the brand-new equivalents are pretty readily available and pretty cheap. (or were, before the current global shortages.)
(huh. The most useful "old" parts have been "indicator" LEDs; the sort of thing you use for "power", TX, and RX indicators on an Arduino board. I've got a reel of 3mm RED LEDs (on sale!), and a drawer full of green 3mm LEDs (pulled from boards and removed from holders.) And they actually get used, when I'm building something that uses TH LEDs.)
Yes, I can't resist salvaging and find it hard to throw things away - I look at something and think "what can I use that for?".
Years ago, there used to be shops and market stalls specialising in junk, especially WW2 reclaimed parts, and mysterious circuit boards.
Exchange and Mart full of 2-way radios.
I still look at PCBs from duff equipment and see if anything is worth recovering, but realistically, there never are, given the effort to get them off the board etc.
It's hard enough keeping track of new components and containers from TicTacs to pocket money envelopes come in handy, plus a large Excel spreadsheet to try and locate the stuff.
The only things I regularly strip for bits are old printers for motors and gears, but HHDs so far have never yielded a motor.
I always remember my first successful electrical experiment with an Ever Ready cell, some fuse wire and a bulb - hooked for ever.
I still rifle through skips and the other day found a 6-ft Stabilo level chucked out because it was slightly bent. Leaned it against the wall and applied some pressure. Job done, now have a £40 level to add to the collection.
I think salvaging and possibly hoarding goes back to times when things weren't so easily available, but I must agree with @westfw, there comes a time when you have to stop and a possible house move is going to force some hard decisions.
On the other hand, buy a bigger house and get more junk room.
I actually used some old printer parts to make a mini CNC engraver for wood using a Dremel. And some parts of another to make a CNC sand (Zen) plotter.
I have a lot of salvaged parts and every once in a while use some. But, I fear, most will not be ever used. I do hesitate to throw them away because I figure that as soon as I do I will have a use for them.
The field between the poles changes uniformly. With a Linear Hall sensor, angles could be read on say a non-ferrous caliper where one arm has the magnet mounted on it and the other arm holds the sensor that moves along the magnet as the caliper opens and closes.
The voice coil runs current through itself to make a certain strength magnetic field inside of the loops. The magnets will try and center the loops where the magnet field average matches the field in the loops, it pushes strongly -- the drive heads move track to track and settle in a fraction of a ms.