Electronics explainers? I thought I knew V=IxR but i’m at P=VxI at best

July 14, 2024 9:19 AM

I’m looking for videos or online courses that teach electrical engineering for low voltage signals.

I’ve been dealing with electrical things professionally for thirty years in entertainment lighting and sound. But I’ve mostly dealt with the big stuff - lighting rigs with power distros up to 400 amps, and audio amps with 200-1200 watts per channel, etc.

I have a number of projects that I would like to build as hobby - mostly small signal, op-amp based devices for low voltage audio and analog control. I also am very good at troubleshooting signal paths on the job, and methodical AB testing, but I would like to know they “why” behind the problems.

So I’m working my way through The Art of Electronics 3rd edition and some basic concepts are extremely difficult for me:

- voltage vs. current, and current sources in particular, are very hard for me to understand. Same with transconductance - the idea that you can input a variable voltage, and get a variable current out, or vice-versa, I find impossible to intuit. Same with power factor - the idea that voltage and current are present in a circuit but not at the same time, breaks my brain.

- Using resistors to set impedance - for example placing a resistor in the signal path for an output feels inherently wrong - see above, what would happen if a bunch of resistance showed up in-line with that 400 amp distro.

Clearly there’s some fundamental stuff I’m not getting.

Ideally I’d go back to a low level electrical engineering class, college level, but that’s not in the cards. I also find so much web content is digital based, thanks to arduino, microcontroller, etc. I am interested in analog only so that’s not helpful.

Can you recommend engaging video tutorials or interactive resources with clear explanations and real-world examples to help me grasp these fundamental concepts? Book recs OK, but I’ve tried a many and bounced off.

posted by sol to Technology (5 answers total)

Might be worth a look at Khan Academy? I haven't used it for science or engineering, but it's well thought of, and I'm a huge fan of their math videos, which I find very useful. It's free, running on optional donations, and a quick look suggests that the introduction to electrical engineering might be useful for some of the fundamentals.

Good luck!
posted by eternalhedgehog at 11:17 AM on July 14, 2024 [1 favorite]

I was you a few years ago! MIT's 6.002 Circuits and Electronics from 2007 is on OpenCourseWare -- all lectures and all problem sets. This covers a little bit of digital but mostly analog. The stuff you're talking about is mostly in the first half of the course. I found it a great companion to The Art of Electronics and wound up designing and building most of a theremin!

Mostly IMO to get a good feel for the stuff you're talking about, you have to just solve a bunch of circuits by hand. Do the problem sets!! The intuition comes after the math -- I don't know of any shortcuts. Solving some circuits with BJTs in them in particular, and then building them to make sure you got them right, will really help build intuition for AoE's "transistor man" model.

I assume you have a scope, but if not, you really do need one to actually see what's going on -- there's no substitute.
posted by goingonit at 11:21 AM on July 14, 2024 [4 favorites]

I've found CircuitJS to be immensely helpful for learning. The UI is a little clunky, but the visualization of voltage and current really gets through to me. There's also graphs for more complex circuits with a time component.

If Practical Electronics for Inventors isn't one of the books you bounced off of, I'd check that out. For me it's the perfect balance of approachable but not so simplified as to be useless.
posted by davidest at 2:44 PM on July 14, 2024

The topics you are looking for are circuits (discrete component behavior, circuit analysis, voltage, current, impedence, resistance, capacitance, inductance, power, time and frequency domains), then intro electronics (diodes, transistors, signals), then upper electronics (linearity, amplification, complex circuit analysis).

The mit resources are good.

iaa ee/ce/software person.
posted by j_curiouser at 4:32 PM on July 14, 2024

the art of electronics is not a trivial or intro text. to me, only useful in upper level engineering.
posted by j_curiouser at 4:34 PM on July 14, 2024