What to put in a HIGH SCHOOL intro electronics course?

[Ecnerwal]

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.)

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

 

On Wednesday, December 2, 2015 at 7:09:00 PM UTC-10, Ecnerwal wrote:

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.

Doesn't exactly sound like an electronics course. It sounds more like you want to create a "maker" course, using electronics. Maker is basically the concept 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 do this to get kids interested in the subject.

Just the soldering alone may take awhile, and may be boring if you start off 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 concept. 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 gates, 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, and then move on up to 7-segment LEDs and BCD stuff.

Here's an awesome audio project to use as a soldering project:
http://www.ebay.com/itm/1Pcs-New-9-15V-Voice-Control-Level-Indicating-Voice-Indicator-Module-DIY-Kits-/291548836254

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 is very easy to troubleshoot. Once they finish building this, they'll have something really cool to take home.

 

[Phil Allison]

Ecnerwal wrote:

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."

** 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 turns on a 2.5 inch former ) and use a germanium diode and piezo earpiece. First to hear a radio program gets a reward.

The theory of operation is not too frightening and most are intrigued by how 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 "flip flop" drive a pair of LEDs. Heaps of basic stuff to learn about with that.

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

 

[George Herold]

On Thursday, December 3, 2015 at 12:09:00 AM UTC-5, Ecnerwal wrote:

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.)

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

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

https://www.dropbox.com/s/he1m9wa78ruq8fc/grab-bag.JPG?dl=0

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.

 

[George Herold]

On Thursday, December 3, 2015 at 12:09:00 AM UTC-5, Ecnerwal wrote:

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.)

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

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

https://www.dropbox.com/s/he1m9wa78ruq8fc/grab-bag.JPG?dl=0

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.

 

[amdx]

On 12/2/2015 11:08 PM, Ecnerwal wrote:

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."

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

 

[Phil Hobbs]

On 12/03/2015 02:39 AM, Phil Allison wrote:

Ecnerwal wrote:


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."



** 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 turns on a 2.5 inch former ) and use a germanium diode and
piezo earpiece. First to hear a radio program gets a reward.

The theory of operation is not too frightening and most are intrigued
by how 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 "flip flop" drive a pair of LEDs. Heaps of basic stuff to
learn about with that.

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

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

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[Phil Hobbs]

On 12/03/2015 10:33 AM, amdx wrote:

On 12/2/2015 11:08 PM, Ecnerwal wrote:
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."

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

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



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[Ecnerwal]

In article <85b32307-8998-48db-ad52-228c30412a17@googlegroups.com>,
groink1@gmail.com wrote:

On Wednesday, December 2, 2015 at 7:09:00 PM UTC-10, Ecnerwal wrote:
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.

Doesn't exactly sound like an electronics course. It sounds more like you
want to create a "maker" course, using electronics. Maker is basically the
concept 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 do
this to get kids interested in the subject.

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. ;^> ]

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

 

[Ecnerwal]

In article <56606B19.1040505@electrooptical.net>,
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

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.

....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.

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.

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

The maker thing is great, *provided you lift the hood and show the
workings*.

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

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.)

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.)

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

 

[Tim Wescott]

On Wed, 02 Dec 2015 23:39:48 -0800, Phil Allison wrote:

Ecnerwal wrote:


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."



** 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 turns on a 2.5 inch former ) and use a germanium diode and piezo
earpiece. First to hear a radio program gets a reward.

The theory of operation is not too frightening and most are intrigued by
how 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
"flip flop" drive a pair of LEDs. Heaps of basic stuff to learn about
with that.

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.

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tim Wescott]

On Thu, 03 Dec 2015 00:08:54 -0500, Ecnerwal wrote:

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.)

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tim Wescott]

On Thu, 03 Dec 2015 09:33:47 -0600, amdx wrote:

On 12/2/2015 11:08 PM, Ecnerwal wrote:
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."

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

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.)

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[ABLE1]

On 12/3/2015 12:08 AM, Ecnerwal wrote:

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.)

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

 

[whit3rd]

On Wednesday, December 2, 2015 at 9:09:00 PM UTC-8, Ecnerwal wrote:

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

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).

 

On Thu, 03 Dec 2015 00:08:54 -0500, Ecnerwal
<MyNameForward@ReplaceWithMyVices.Com.invalid> wrote:

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.)

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

 

On Thursday, December 3, 2015 at 7:24:42 AM UTC-10, Ecnerwal wrote:

In article <85b32307-8998-48db-ad52-228c30412a17@googlegroups.com>,

On Wednesday, December 2, 2015 at 7:09:00 PM UTC-10, Ecnerwal wrote:
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.

Doesn't exactly sound like an electronics course. It sounds more like you
want to create a "maker" course, using electronics. Maker is basically the
concept 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 do
this to get kids interested in the subject.

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. ;^> ]

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

My background is more in education than electronics. If you're using this course 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 electronics 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. In this case, it was a roulette wheel that made a sound while the LEDs lit up 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 simplified 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 computer. 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.

 

[szczepan bialek]

"Tim Wescott" <seemywebsite@myfooter.really> napisał w wiadomości
news:mqadnY9tbolQGf3LnZ2dnUU7-bkAAAAA@giganews.com...

On Thu, 03 Dec 2015 00:08:54 -0500, Ecnerwal wrote:


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.

Here you are the simplest form:
https://en.wikipedia.org/wiki/Crystal_radio#mediaviewer/File:Simplest_crystal_radio_circuit.svg

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.

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

 

[Frnak McKenney]

On Thu, 03 Dec 2015 11:55:06 -0600, Tim Wescott <seemywebsite@myfooter.really> wrote:

On Wed, 02 Dec 2015 23:39:48 -0800, Phil Allison wrote:
Ecnerwal wrote:

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."

[...]

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.

Hi, Tim.

Would you believe I made one from two squares of masonite swiped from my
father's wood box, bolted together at one corner, each square covered
with tinfoil and an insulating layer of waxed paper between?

You tuned it by pivoting one square against the other -- highly
nonlinear, but it did vary the capacitance.

I like your approach better. <grin!>

I did some searching and found this, which looks like what you were
describing. It's also a neat cheeeep DIY radio design:

http://rimstar.org/science_electronics_projects/loop_antenna_portable_crystal_radio.htm

Here are a few variants:

Soda Can Variable Capacitor
https://www.youtube.com/watch?v=YWLVZ8dF5oo

How to make DIY Variable Capacitors.
https://www.youtube.com/watch?v=xJHygzNIV24

I also discovered this one, which caused an immediate "Well, duuuuuh!"
reaction and a wish I'd had the imagination to come up with it myself
(and you don't need a laser cutter!):

http://www.crystalradio.net/beginners3/cap.shtml

This one is a bit more effort, but looks more like the commercial type:

http://www.eham.net/articles/5217

Did you ever try making a pencil-lead-and-razor-blade detector? I never
succeeded in making one work, but they were described often enough to
make me believe they could. If you never saw one, here are a few links
I just dug up:

http://bizarrelabs.com/foxhole.htm
http://blog.jgc.org/2012/02/my-foxhole-radio.html
http://www.n6cc.com/crystal-radios-it-started-here
http://sci-toys.com/scitoys/scitoys/radio/homemade_radio.html
http://nandustips.blogspot.in/2013/05/foxhole-radio-detector-variant.html

Apparently being stuck in a foxhole under combat conditions inspired a
lot of creativity. <grin!>


Frank McKenney
--
It is important to resist the temptation to reduce human motivation to
an economic desire for resources. Violence in human history has often
been perpetrated by people seeking not material wealth but recognition.
Conflicts are carried on long beyond the point when they make economic
sense. Recognition is sometimes related to material wealth, but at
other times it comes at the expense of material wealth, and it is an
unhelpful oversimplification to regard it as just another type of
"utility". -- Francis Fukuyama / The Origins of Political Order
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank u.score mckenney aat mindspring d.ot com

 

[Phil Hobbs]

On 12/04/2015 12:10 AM, groink1@gmail.com wrote:

On Thursday, December 3, 2015 at 7:24:42 AM UTC-10, Ecnerwal wrote:
In article
85b32307-8998-48db-ad52-228c30412a17@googlegroups.com>,

On Wednesday, December 2, 2015 at 7:09:00 PM UTC-10, Ecnerwal
wrote:
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.

Doesn't exactly sound like an electronics course. It sounds more
like you want to create a "maker" course, using electronics.
Maker is basically the concept 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 do this to get
kids interested in the subject.

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. ;^> ]

-- Cats, coffee, chocolate...vices to live by Please don't feed the
trolls. Killfile and ignore them so they will go away.

My background is more in education than electronics. If you're using
this course 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 electronics 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. In this case, it was a roulette
wheel that made a sound while the LEDs lit up 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 simplified 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 computer. 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.

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

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net