What to put in a HIGH SCHOOL intro electronics course?

I'm contemplating offering a basic, assume nothing electronics course during the "winter-session" at our school. 17 meetings over 5 weeks totaling about 40 hours.

I want to offer basic concepts and hands-on, use a soldering iron, make stuff. Without treating it as magic, I'm also facing the fact that there's no assuming that the students will have had any advanced mathematics, so I'm going to need to step away from messy math and stick to simple stuff and the occasional "you'll learn more later."

By the time I actually _learned_ any of this stuff, I'd had 4 semesters of college engineering math and 1 or 2 barf-back EE courses that taught me nothing of use. Then I took electronics for physics and the textbook was AoE and the focus was on understanding things, not just memorizing what gain formula went with what resistor configuration around an op-amp.

But I can't really see trying to force feed AoE (though I still like it) to high school students (nor make them buy it for a 5 week course that won't work far into it.) On the other hand, I'm certainly not looking to repeat my glorious barf-back (rote memorization) experience, which really was a waste of a class.

I can probably limit the class to 5 or 6 students, (it's one of many offerings in a small school) and meeting times are all long enough to get some hands on in every session.

I don't have much of anything nailed down yet, but will need to do so by January (and decide if I'm gong to take a stab at it by Saturday.)

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Reply to
Ecnerwal
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Doesn't exactly sound like an electronics course. It sounds more like you w ant to create a "maker" course, using electronics. Maker is basically the c oncept of just making stuff, and not really need to know the theory behind it. Just follow steps A-Z, and boom you have made something. Most schools d o this to get kids interested in the subject.

Just the soldering alone may take awhile, and may be boring if you start of f with this since one can't build anything until he learns soldering. So I' d start off using solderless breadboards. Design a few kits using this conc ept. And then maybe bring soldering into the course later when they already have a few built kits under their belt.

I do hope that they do get the very basics out of this - especially logic g ates, since this will be vitally important if they do pursue further. Logic gates isn't really math. Actually, it may be fun to give them a few logic gates projects. Start off small like playing with LEDs and 74 series ICs, a nd then move on up to 7-segment LEDs and BCD stuff.

Here's an awesome audio project to use as a soldering project:

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Some good things about this kit: The kit is cheap! The solder pads are big, the board is one-sided, and the silkscreen documents everything. And, it i s very easy to troubleshoot. Once they finish building this, they'll have s omething really cool to take home.

Reply to
groink1

** After teaching them to solder - why not divide the class into two teams and get each to build a "crystal" radio. Have them wind the coil ( 120 turn s on a 2.5 inch former ) and use a germanium diode and piezo earpiece. Firs t to hear a radio program gets a reward.

The theory of operation is not too frightening and most are intrigued by ho w few parts are essential to make a working AM receiver. Obtaining a couple of usable tuning gangs could be an issue, if no old radios can be found.

Then they can move on to *semiconductors* by making a two NPN transistor "f lip flop" drive a pair of LEDs. Heaps of basic stuff to learn about with th at.

They should all learn to read resistor colour codes, any teenage girls will likely think they look cute too.

I started out with "body-end-dot" types but you can give that a miss.

... Phil

Reply to
Phil Allison

How about teach and build a basic linear power supply.

What does the transformer do? What does the bridge rectifier do? Ripple What does the filter cap do? Filter size What does this series resistor do? Why did it get hot? Oh so if we use two-1/2 watt resistors instead of one! What does the zener diode do? What does the Pass transistor do? What is the load. What is the load current.

There is a whole lot of learning in there. Transformer ratios, different filter caps, current flow through the bridge rectifier, AC to DC, Ohms law, setting current flow in the zener, the transistor voltages. You can dig as deep into each section as your time will allow.

Mikek

Reply to
amdx

Just make sure to teach them the clean version of the mnemonic. ;)

Cheers

Phil Hobbs

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Reply to
Phil Hobbs

Some of JL's open-gate MOSFET tricks are fun. I might start with static electricity (sticking balloons to the ceiling works well in Mass in the winter), then do a FET demo, which naturally takes you into the idea of current and voltage. FETs are a lot easier for people to understand.

I'd probably steer clear of inductance except as a mention, but capacitance is easy to demonstrate with a small water tank and pressure gauge, or even a balloon and air pressure, except that the pressure vs volume curve is nonlinear for a balloon.

BJTs are hard enough to explain that I'd stick with FETs for the most part. 2N7000s are cheap enough that it doesn't matter how many they blow up.

The maker thing is great, *provided you lift the hood and show the workings*. People tend to think that using canned Python libraries to make a RasPi blink a LED makes you a techie.

Doing it with a 555 makes you learn something, even if it's on one of those miserable white protoboards. (New ones are OK for awhile, till somebody sticks in a TO220 or a 1-W carbon resistor and bends the metal out of shape.)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Reply to
Phil Hobbs

Not really - too many "makers" are _very_ voodoo/magick about how things work, and I'm shooting a bit higher than that. But I'm not aiming for the Maxwells equations approach (MIT 6.002 is a lovely on-line course, but scares HS students in my experience - unless you just fast forward to the glowing pickle at 36:45 in the first lecture.) But I do want this to be a hands-on laboratory course.

I did teach ~600 freshmen engineering college students to solder a few decades back, so I'm good with that part, though there will likely also be some protoboard. [I think I'll leave the nitrogen laser out of this course, though - the thyratron alone would blow my budget. ;^> ]

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Reply to
Ecnerwal

...and that's worth the price of admission. I suspect you are right, but it's not something I'd likely have come up with myself.

Killing parts is fully expected. Otherwise they will have missed something they should know about.

Eggs-act-ly where I'm trying to get to.

I know well the foibles of proto-boards - I had a different lab with 3 of them tied to each of 20 computers that I had to keep functional (also a couple of decades back.)

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Reply to
Ecnerwal

You can make a very satisfying capacitor suitable for a crystal radio with a toilet paper tube, two pieces of tinfoil, and a sheet of waxed paper. I was rather astonished that it worked at all, but not only did it work, it was fairly easy to peak up a station.

I can't remember if you drew the moving sheet of foil up off the tube or if you twisted it around -- the principle is that you use the waxed paper as a dielectric, and bring the tin foil plates more or less into alignment by twisting or pulling.

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Tim Wescott 
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Tim Wescott

I would start with light bulbs or LEDs and batteries. Use the force/ speed analogy for voltage and current (the battery pushes, the current flows, yadda yadda).

LEDs and resistors would make a good experiment -- not only do you get to show them that diodes only work one way, but you get to show them that more resistance = less current, and you give them about the simplest currently available circuit that one can use to annoy a sibling.

Just showing them that a light comes on when the circuit completes should be cool for the susceptible ones. Make sure to explain that a switch really isn't much more than a couple of pieces of metal that come together or not, with specially-chosen metal for long life and a mechanical arrangement that makes the metal bits do what you want.

In forty hours of instruction if you can get them from nothing to soldering and understanding what makes a circuit work, then you've accomplished something. If you can get them there and have some of them interested in carrying on, you've accomplished a lot.

Particularly if it's early high school and middle school you may not want to push the soldering too hard -- today's soccer moms are going to be more comfortable with twisted wire and rubber bands than with soldered-up circuits (alas). I'd still show the kids how to do it, though.

I think Phil's crystal radio idea is good if you can work it in. The one that I built with my kid was no-solder, used screws from the hardware store as necessary for connections, and was built on a shoebox for a chassis with toilet paper rolls or sections of wrapping paper rolls hot- glued onto the shoebox for coil and cap formers.

One of the educational opportunities it presented was the tradeoff between germanium diodes (more sensitive, die with every distant lightning strike) vs. silicon diodes vs. schottkey diodes (hard to find small-signal ones, but they work great) vs. CB and BE junctions of transistors.

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Tim Wescott 
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Reply to
Tim Wescott

Good idea EXCEPT that half of the job, IMHO, is selling the students on electronics. Unless you're already sold, a linear supply is going to be boring.

(Hence my suggestions about lights and crystal radios -- and maybe motors, too. They're still fairly useless, but they put people closer to being able to see how they _could_ be useful.)

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Tim Wescott 
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Reply to
Tim Wescott

Hi Lawrence. Hey I've been collecting the resistors and other dross off my lab bench in a bag.

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Less than I would have thought, but I've been doing less electronics lately. It sounds like you may be ready for it, send me an address and I'll stick it in the mail.

So what type of test gear will you have? DMM's, 'scope, sig. gen.

Do you know of the tap-l listserver.. mostly college level physics demo guys but there are some HS teachers too. They may have some good advice for you. I think it's hosted out of NC State.

Probably at too high a level but there is ZAP! experiments in electrical currents and fields. Hmm there is a free pdf at MIT but a bit different from my book.

I would try for simple... with a bit of fun. Tim's led's, batteries and light bulbs, maybe some RC circuits. (Are they going to plot data... you can do a long RC with a big cap and the 10 meg ohm of a DMM and record the voltage and time with a stop watch... then they have to figure out how to plot it. I guess that's too advanced also.)

For the fun part I also like the AM radio idea.

George H.

Reply to
George Herold

Hi Lawrence. Hey I've been collecting the resistors and other dross off my lab bench in a bag.

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Less than I would have thought, but I've been doing less electronics lately. It sounds like you may be ready for it, send me an address and I'll stick it in the mail.

So what type of test gear will you have? DMM's, 'scope, sig. gen.

Do you know of the tap-l listserver.. mostly college level physics demo guys but there are some HS teachers too. They may have some good advice for you. I think it's hosted out of NC State.

Probably at too high a level but there is ZAP! experiments in electrical currents and fields. Hmm there is a free pdf at MIT but a bit different from my book.

I would try for simple... with a bit of fun. Tim's led's, batteries and light bulbs, maybe some RC circuits. (Are they going to plot data... you can do a long RC with a big cap and the 10 meg ohm of a DMM and record the voltage and time with a stop watch... then they have to figure out how to plot it. I guess that's too advanced also.)

For the fun part I also like the AM radio idea.

George H.

Reply to
George Herold

I would like to contribute to the thoughts on starting an electronics/electrical course. May I be the first to say that the story you are about to read really happened. I would strongly suggest that the circumstances never be repeated since it could have gone a totally different way, as most here would/should agree.

The year was 1965. The school district decided that they should start a Basic Electrical/Electronics course to offer to those students that signed up. (it was the beginnings of Vo-Tech). So, they emptied out a storage closet in the High School and moved in a bench with a wood(maple) panel box about 6 feet long that had, powerstats, volt meters, amp meters sockets, connectors and test cords, etc. It was really COOL.

About 10 senior guys signed up for the new course, me being one of them. The instructor was the wood shop teacher. Who by the way had sawed off the tip of his thumb (twice). While demonstrating how to use a band-saw the first time. And demonstrating how he did it the second time.

On the very first day of class the instructor explained what the course was about, etc, etc. He then said we could do a practical demonstration of electricity. He asked for a volunteer and the 9 other guys stepped back one step.

The demonstration would be for me to hold two probes that were patched into two sockets as well as to volt meter. The instructor told me to hold on as long as I could and he would shut it off when I told him. He then started to turn the powerstat up from zero. As he rotated the voltage meter increased. At 25vac no effect. At 30 to 40 vac I started to feel a tingle. At 60 vac my arms and hands started to shake. At 75

- 80 my hands started to rotate inward and at 90 vac I said OK that's enough. He then backed off on the powerstat and then rotated to max

100% against the stop. It was at this point that I came off the stool and jumped back against the wall pulling the leads out of their sockets. Everybody got a good laugh. As I was catching my breath the class bell rang and it was off to Spanish II class (which I failed, but that is another story).

What is the lesson here?? Listen to your elders and don't do dumb stuff like we did!!

Have a nice day.

Les

Reply to
ABLE1

Greetings Lawrence, As a basic electronics kind of guy myself I think that transistors are especially important to understand. All sorts of stuff can be made to work that needs to be powered on somehow. And if the stuff is controlled somehow by timer or by light or sound or similar a transistor is often the switch. Even if it controls a relay. So the basic Ohm's law stuff and basic capacitor and inductor stuff, like why caps can be used to filter DC ripple and how an ignition coil works, diodes and transistors are what I think would help your students the most to start loving electronics. Turning on LEDs and motors, fans for example, is fun and can be practical, and making sparks is always fun. I also really like the suggestion to build crystal radios. Especially the toilet paper tube capacitor. That kind of stuff tends to take away some of the mystery while at the same time adding some mystery and encouraging curiosity. Good Luck! Eric

Reply to
etpm

A good way to start, teaching Ohm's law and two-resistor attenuators, is with a meter stick and a thin wire, driven by a low voltage source.

A slide-wire potentiometer is VERY easy to grasp. Then you move on to complete circuits (gotta put both probes to the wire, or no needle movement) and high/low impedance (two V-meters at the same time, same V measured; one V-meter and one shunt resistor, and the V measurement dips).

Reply to
whit3rd

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My background is more in education than electronics. If you're using this c ourse to reel students into getting interested in electronics, the best way to go about it is for them to, right out of the gate, start building stuff that's cool, and worry about the theory later. When I took basic electroni cs in high school, the one great thing my teacher did was allow me to walk out of the class with a cool project within the first two weeks of class. I n this case, it was a roulette wheel that made a sound while the LEDs lit u p around in circles.

I recently taught an intro digital electronics course. And, I did the same approach. But this time, the students built an Apple 1 replica, using a sim plified design with only a few caps and resistors, a 6502 CPU, a 6821 PIA, and a propeller chip. And with it, we did other things with it like turning on LEDs through BASIC. The students walked home with a fully functional co mputer. This is the kind of thing that keeps students engaged. I'm not sure what your budget is, or if you're going to charge lab fees. Something like an Apple 1 can be built under US$50.

Reply to
groink1

Here you are the simplest form:

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I bet that nobody know why the silicon diodes do not work in such circuit. S*

Reply to
szczepan bialek

_That_ is a cool class. Can I sit in on your next one?

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

I would start with an old elcheapo analog scope and a similar quality speak er such as from a little transistor radio. Start with it at a low sweep spe ed and let one of them with a decent voice sing a note into the speaker and watch the scope.

At the slow sweep you see like an envelope but them have them keep it up an d crank up the sweep speed until you can see the waves. (of course you are on autotrigger)

Have another speaker laying around, a bit bigger one and tear it apart so t hey can see it is basically a magnet and a coil like many motors.

Actually I would start with the scope and a battery. That demonstrated DC. THEN move on to the little speaker that acts as a microphone.

Then you get to the explanation of just WTF happened here. It should get th eir interest enough.

Whatever you do, don't bore them with the chemical reaction of a lead acid storage battery like they did me. And all the formulae can wait.

I would put Ohm's law up on the board and tell them to ignore it. Then go o n with the headlight story.

Your car headlights are 36 watts. They get 12 volts and they pull 3 amps. T hey pull three amps because they are 4 ohms. Volts and amps are quantities, Ohms are the ratio between these two quantities. Explain it that way.

And whatever you do, when you get to the little bit more advanced stage, DO NOT conflate out of phase with polarity. I have almost gotten into fights over this. Out of phase is NOT the same thing as out of polarity, just look at a sawtooth wave. For symmetrical waves it can almost be considered so, but do not leave out that important fact from their basic understanding.

Anyway, the cathode ray oscilloscope and an analog meter are very useful vi sual aids. If the class isn't really tiny, you might want a camera and a TV to enlarge it so they can all see it. These days that shit is not expensiv e. If you have a budget to do it that is great, but even if you buy it on y our own you still have it, and it won't break the bank.

Reply to
jurb6006

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