Since you brought it up, all flashlights will at some point stop working unless you shake them or unscrew them and reseat the contacts. That’s the cheap ones and the expensive ones, the incandescent ones and the LED ones.
In the long run, everything stops working.
I teach some basic electrical classes to new contractors and I think I need to borrow this cartoon.
It also illustrates the most basic principle in understanding Ohm’s Law: It takes one volt of potential (pressure) to push one amp of electrons through one ohm of resistance. (Please forgive the over-simplification.) How many volts does it take to push two amps through the same resistance? Two volts.
This is a surprisingly difficult concept to get across to some people. I’ve had people state, “Man, I don’t understand why this power supply and circuit is drawing so much current!” It’s because the load resistance is lower than it should be. That’s it. If the source voltage is the same, the load resistance must be lower. Nothin’ fancy about it.
Yea, someone gave me those little books when I was a kid. But I was so poor that I couldn’t even afford the electronic components in the projects. There are PDFs of them online. Looking at them now, I’m not sure I’d recommend them. Some of the designs are very unconventional, and not in a good way.
Thousands of YT videos exist for someone who wants to learn about electronics, with greater and lesser degrees of quality and utility. Some of my favorite channels include:
Mr Carlson’s Lab. A younger guy from Canada. He is an expert at fixing & restoring older electronics. The guy is amazing, and the Real Deal™. I just watched one of his videos where he describes the uses for different types of capacitors (mica, polystyrene, tantalum, etc.). The video is so informative that I am going to watch it again and take detailed notes.
Aaron Danner. An American EE prof who lives in Singapore. He teaches the fundamentals of electronics from an academic perspective, not surprisingly. But he is very good at it. I especially like his videos on transistors.
Alan Wolke. He’s an engineer at Tektronix. He’s very good with RF circuits, and a wizard at using the oscilloscope. Very hand’s-on. I do not recommend his videos for beginners, though.
David Jones at EEVblog. Australian. Very informative (and humorous) videos, with an emphasis on instrumentation. The forum is also good.
Aaron Lanterman. EE prof at Georgia Tech. Good videos, but primarily aimed at EEs.
Colleen Fazio. Tech wizard from Los Angeles. She repairs old guitar amps. Very informative. (And as a CIS male… nice to watch. Sorry, I’m just being honest.)
ElectroBOOM. He grew up in Iran and now lives in Canada. His earlier videos focused on the comedic aspects of “Don’t try this at home, kids,” and are truly hilarious. Lately he has been getting a little more “serious,” and has been making educational videos.
Thanks! I will bookmark the ones you say are accessable to beginners.
True enough, but certain things need to be pointed out and shamed. Flashlights in particular. The basic design of them - one or more batteries in a compartment, depending on a spring and a piece of brass that slides up and down to complete a circuit that lights a lamp, whose base is touching the top of a battery, has not changed since the late 19th century. There are variations, but they all have the same problem in that components depend on metal touching metal with something pushing the metal pieces together, but eventually things loosen up and it stops working, or sort of works but you have to jazz it which can be very fiddly and not what you want when you’re in a dark cellar trying to find the fuse box or that stash of old albums or whatever.
Another bad thing: Flourescent tube lighting.
Those damn lamps with the little pins on both ends, and you’re up on a stool rotating them back and forth, trying to get them to light properly instead of just a flickery purple glow, but the tubes are blackened at the ends because they’re damaged by being poorly seated for too long, and all your fiddling causes the tube the fall out and smash on the floor, and your smarty-pants nephew tells you “you got a bad ballast, the ballast needs to be replaced”. That.
I’m with you there. I HATE fluorescent lights. They flicker, fail to come on quite often and don’t seem to last any longer then the old incandescent bulbs anyway.
Hopefully LED lights will be an improvement.
I have four or five LED flashlights in the house, and none of them use the sliding contact mechanism to complete a circuit. They all have push-button switches. I’ve never had to shake or reseat the battery in any of them either.
You might enjoy Spintronics, a mechanical circuit building kit/game that uses chains instead of wires, with mechanical equivalents of all the basic electronic components. It claims to make circuits “tangible, irresistibly touchable, and deeply intuitive”.
I used to have the Snap Circuits Pro set.
As the name implies, rather than needing to snip and connect wires, all the components are mounted on hard plastic pieces that attach with metal snaps. It was both educational and an awful lot of fun. Eventually, I gave the set to a friend’s child.
I kep the Snap Circuits RC Rover . It was just too cool not to keep. I had no idea it sold for so much! I bought mine complete in box at Goodwill for about $10. I bought the Snap Circuits Pro kit earlier at a Goodwill for $15. It was also complete and in working order.
I have much to learn about electricity. I have mastered Goodwill.
You will. Anything using a removable battery, and that includes rechargeable power packs, is subject to contact failure, and it doesn’t even have to be corrosion from acid leaks or anything that obvious. If there’s a teensy bit of slop in the construction, it will break your heart sooner or later. Push buttons are some of my worst enemies, especially the ones with rubber seals over the buttons which are supposed to seal out the Elements but somehow don’t and just make spraying contact goop to rejuvenate a bad button impossible.
Interesting. Chains, huh? Might give it a try since I always wanted to build my own Enigma machine for coding secret messages to my underground antiterrorist cell.
Well, at least two of my flashlights do not have removable batteries. They are completely sealed units with a USB socket for charging.
I still haven’t gotten one of those shake flashlights with a rare earth magnet that never needs batteries. I found one when we were going through my Dad’s stuff after he passed. Mom said I could have it. I explained that it never needed batteries and how to charge it by shaking. I also explained that as she lives in south Florida and her specific area routinely gets hurricanes, she needed it way more than I did.
Well, shaking flashlights provides you with some exercise so I suppose there is an upside.
Anytime someone explains the basics of electricity, I just politely nod, pretend like I understand, and hope the conversation ends so I can go back home, eat a tub of ice cream from a freezer powered by a mysterious power source I don’t understand, and watch Full Metal Jacket for the fiftieth time on an electronic device once again propagated by this bizarre black magic.
The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far.
— H. P. Lovecraft, “The Call of Cthulhu” (1928)
To be fair:
Flashlights are rechargeable now. I have a little (magnetic!) flashlight that gives more light than a 5D maglight and has 0 moving parts or connections that can corrode.
Fluorescent light tubes are a victim of their own succes.
Efficient, cheap light since 1935: of course that design leaves something to be desired. Happily we have led panel that fit in place of standard ceiling tiles now.
Going back to the OP, I think one of the biggest problems w/ trying to understand this stuff is that some of what is taught, and even the terminology, is flat-out wrong. Students are deceived, so it’s no wonder they’re confused. Bill Beaty talks about this quite a bit on his website.
One example (of many) is the very common term “AC.” The instructor will point to an outlet on the wall and tell you, “The voltage at that outlet is AC.” AC, of course, being an acronym for alternating current.
Well, it might be. Or it might not be.
If nothing is plugged in to the outlet, is there an alternating current at the outlet? No. The current is zero. Then why are we saying it is AC? Do you see the problem here?
If you point this out to the instructor they will say, “True, but I am assuming something is plugged into the outlet. It is AC when a load is connected. Ha!”
Well, it might be. Or it might not be.
So right off the bat, the student is learning wrong - or at the very least, incomplete - info, and memorizing wrong terms. Some of these students will later become instructors, and the wrong/misleading info perpetuates forever.
As for the wires that are inside the walls of your house and going to your outlets, a much better description for the electricity is AV (alternating voltage), not AC. But good luck trying to change that.
AC Supply is the full term that is rarely used.