MIT 6.002 - Circuits / Systems
The Legend, in horrible 240p from DV, Anant Agarwal will teach you electronics basics without fail.
If you can't get it from him, chances are you won't get it from anyone else - his explanations are to the point and lacking any esoterics, and the best part is, this is probably -don't tell anyone- the most hilarious class you'll see in a long time, whether you're at MIT or not.
This was an experiment to get the LM3915 and 3916 to cascade and do Dot and Bar mode in Multiplex.
Starting with an Astable Multivibrator, Logic Circuits are used to generate square waves that modulate the Dot and Bargraph drivers between the respective modes and multiplex their inputs between Peak and Average.
A tad highly elaborate, too much for most applications, they are fun to build and have that certain "slip" that only analog meters do.
How to NOT Mill a PCB
Great Scott! In this video, the YouTube content creator of the same name goes on to tackle the subject of PCB milling. Most of the industry is based, for good reasons, around photochemical processes, but for prototypes or PCBs that require special isolation, milling has its place.
And considering there's enough to screw up when milling something 35µM thick, it's good when you have some info before you fire up the CNC.