 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
|
 Posted: Sat Feb 13, 2010 8:25 am Post subject: Basic Electricity....Grrrrr......... |
 |
|
Perhaps the stars are misaligned, but I keep getting calls like this:
"I bought your PowerSchottky Diode and it has voltage both ways. Don't you check this stuff before sending it out?..."
"I bought your Powerlink Jr. III 35 amp relay and it won't turn (on or)off...the output still has voltage..."
I could go on. I often forget that in the "basic electricity" world the existence of a voltage is presumed by many to mean something is ON. I need to include a "This means nothing at all" note in my instruction manuals.
Solid state devices often use "pull-down" (or pull-up) resistors to prevent outputs from "floating". But this is done to prevent odd things from happening-- not usually to prevent voltmeters from reading something silly.
Now this is not a unique characteristic of solid state devices. Any typical electromechanical relay will have some voltage on its power output lugs whether it is on or off, only the impedance will be different. A voltmeter with no load is pretty useless (but hey, it could be made to give nonsensical readings on those ghost-hunter shows).
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
|
| Back to top |
|
 |
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Sat Feb 13, 2010 9:52 am Post subject: Basic Electricity....Grrrrr......... |
|
|
At 10:26 AM 2/13/2010, you wrote:
Perhaps the stars are misaligned, but I keep getting calls like this:
"I bought your PowerSchottky Diode and it has voltage both ways.
Don't you check this stuff before sending it out?..."
"I bought your Powerlink Jr. III 35 amp relay and it won't turn (on
or)off...the output still has voltage..."
I could go on. I often forget that in the "basic electricity" world
the existence of a voltage is presumed by many to mean something is
ON. I need to include a "This means nothing at all" note in my
instruction manuals.
Solid state devices often use "pull-down" (or pull-up) resistors to
prevent outputs from "floating". But this is done to prevent odd
things from happening-- not usually to prevent voltmeters from
reading something silly.
Now this is not a unique characteristic of solid state devices. Any
typical electromechanical relay will have some voltage on its power
output lugs whether it is on or off, only the impedance will be
different. A voltmeter with no load is pretty useless (but hey, it
could be made to give nonsensical readings on those ghost-hunter shows).
May I suggest some words in your download/handout
literature that speaks to errors of deduction that
arise from errors of measurement? Some simple test
procedures can stand off many unhappy returns from
customers that do not understand the physics of our
art.
While multi-meters still had pointers moving over
scale plates behind glass, there was no such thing
as a VOLT METER. The meters were in fact sensors of
current. They could be made to display voltage by
placing a resistor in series with the instrument. E.g.
a 0-1 milliampere meter movement might be placed in
series with a 20K resistor and be fitted with a scale
plate that reads from 0 to 20 volts. With a sensitivity
of 1000 ohms/volt, this device would have yielded
better data for your un-educated customers. During
this same era, we had to go out of our way to craft
voltmeters with VERY high sensitivities (Vacuum Tube
Voltmeters) that would not load a voltage node driven
by a particularly high impedance.
Even with all the accuracy and non-loading effects
of modern digital voltmeters at DC, they present a whole
NEW problem when attempting the measure voltage at nodes
where there are radio frequency components riding on
the DC. The old VTVM had a resistor (1 to 10 megohms)
built into the probe right at the tip. The modern digital
meter expects to tell you what the voltage is a end
ends of some long wire leads.
I have adapted a 'scope probe to a 3/4" banana plug
such that I can scale any of several digital meters
by a factor of 10 while taking advantage of the
very low capacitance/high resistance loads presented
by the 'scope probe.
Our customer base is the amateur airplane builder.
By definition, they're NOT professionals in the
broad spectrum of skill sets applicable to the
task. Hence, the events you've cited should be
expected on some level. I'm disappointed to report
that the ranks of those who truly understand the
physics of our art are getting pretty thin . . .
even amongst professionals with credentials that
suggest otherwise.
The market we have is the market we have. We can
choose to service it with what's necessary and
useful to move the various projects ahead or
. . . the alternatives are obvious.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
XeVision
Joined: 07 Oct 2009
Posts: 26
Location: Ogden, Utah
|
| Posted: Wed Feb 17, 2010 3:18 pm Post subject: Re: Basic Electricity....Grrrrr......... |
|
|
We encounter an even more basic issue on occasion regarding 12 or 24Volts availability at the ballast.
Once in a while, we get the call "I have 12 volts at the ballast input connector but the light does not come on when I hook power to it". My response is typically, try measuring the voltage at that location with a load on it. Either our system, a light bulb (incandescent) or other load.
Do you still have about 12V or 24V with the load or does the voltage plummet as soon as a load is applied. If so, look for corroded connections in the wiring, a bad switch, a bad ground, etc.
Sometimes they are using the airframe for ground (not our preference) and sometimes the airframe at that location is not well grounded back to the neg bus/ neg bat terminal.
People building airplanes, if they do any of the electrical work, should learn some basics of how electrical circuits work. When they don't understand these basics they automatically blame the non operational component(s).
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
LED still has a long way to go to compete with HID as a landing light. This is true in terms of total lumens and reach (distance). |
|
| Back to top |
|
|
rampil
Joined: 04 May 2007
Posts: 870
|
| Posted: Thu Feb 18, 2010 8:29 am Post subject: Re: Basic Electricity....Grrrrr......... |
|
|
On the other hand, there's the observation in the Avionics-List last Friday
that noted if there was any electrical (not even electronic) literacy, out
there, the traffic on this List would drop by 90%.
I would think Bob's Seminars would be much more popular!
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Ira N224XS |
|
| Back to top |
|
|
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Thu Feb 18, 2010 10:13 am Post subject: Basic Electricity....Grrrrr......... |
|
|
At 10:29 AM 2/18/2010, you wrote:
| Quote: |
On the other hand, there's the observation in the Avionics-List last Friday
that noted if there was any electrical (not even electronic) literacy, out
there, the traffic on this List would drop by 90%.
|
Not sure that's true . . . folks gravitate into groups
for a host of reasons. I suspect the participation here
is mixed. Certainly there are individuals who seek
customer service style yes/no answers to immediate
decisions/problems.
It has always been my goal that this be more of a
classroom than a "customer support" activity.
And given the size of the list (about 1700 at last count)
and relatively low traffic, I suspect that most are
here to expand their horizons.
This is why I (and I'm sure most others) welcome information
and ideas that help us DO things with cgreater onfidence,
understanding and competence.
| Quote: | I would think Bob's Seminars would be much more popular!
|
I've been rethinking the weekend seminar format as
a teaching tool. It's a drink-from-a-firehose which
probably has a lower rate of retention than a 3-hour
college course . . . which also has a demonstrably poor
retention rate.
I've been watching my 2.5 year old grandson with
great interest. We humans are blessed with a great
deal of potential but the process by which that
potential is exploited is torturously slow. Retention
of ideas and acquisition of skill comes with
close attention and interest over long periods
of time. The most capable among us did not get
that way by taking a course. They acquired it over
years of hands-on activity and often in the company
of true teachers.
This is why Mr. C's parents and grandparents are
attentive to the idea that every day experiences
should to be framed as teaching moments. What is
that? How does it work? Is it easy to break?
Can it hurt you? Are there inappropriate usages
that attack the liberty of others or destroys
property? I'm not suggesting that this little
guy is being treated like a high-school student . . .
certainly everything offered has to be tailored
to his level of understanding. But the process
of becoming 'educated' goes far beyond any time
one spends in the formal classroom. One gets
and holds his attention by making it fun.
The AeroElectric-List is an opportunity for
the interested and attentive to read about ideas
and their supporting physics go by over as
long much time as one is willing to expend
on the effort.
This is why I encourage folks to write about
any whippy new discovery, any unexplained
event (contactor failures?), or ask any question.
It's then up to those who can contribute to
an exploration of the question or understanding
of the answers have an opportunity to become
true teachers.
We all have things to learn, things to offer
and opportunities to share in the pleasure of
advancing our collective art. The process is
slow and laborious . . . and the older we get,
the more laborious it becomes. One of my
teachers once opined, "The day you stop learning
the first day of your decline toward insignificance."
Mr. C is one of my strongest motives to add to
my own catalog of understanding and skills to
share with him as he grows up. Folks here on
the list are participants in that task. You
all contribute to expansion of my own horizons
which I will ultimately pass down to the next
generation.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
MauleDriver(at)nc.rr.com
Guest
|
| Posted: Thu Feb 18, 2010 11:15 am Post subject: Basic Electricity....Grrrrr......... |
|
|
rampil wrote:
| Quote: |
On the other hand, there's the observation in the Avionics-List last Friday
that noted if there was any electrical (not even electronic) literacy, out
there, the traffic on this List would drop by 90%.
I would think Bob's Seminars would be much more popular!
--------
Ira N224XS
I think the level of electrical, and even electronic, literacy is a bit
|
higher here than one might think.
An analogy I might make is with instrument flight. I'm IFR literate
(talk the talk, been there-done that, remember most rules, read most
pubs), but not proficient or current. Having grown up with my Dad's
scratch built TV, testing vacuum tubes for fun, studying for my Class
III, practicing morse code, recyling components from surplus boards, and
building pre-proportional RC aircraft, I'm electrically literate but not
proficient or current. And 30+ years in the computer industry doesn't
necessarily cover the same ground.
For those of us not in the business or practicing an
electrical/electronics hobby on a daily basis, this list is a pretty
good substitute. Of course fooling around with OBAM aircraft can be an
electrically engaging pursuit... and I think what we all see here is a
lot of literate people building skills while regaining a little currency
and proficiency as they work their projects.
Ohm's law?? On at least 2 occassions over the last year I can recall
relearning that simple little equation as a fuse fried or some unit
dimmed. I learned it, I know what it is, but haven't applied it in so
long that a little rediscovery is to be expected.
Anyway, I'm REALLY enjoying this list and everyone on it. Thanks to Bob
in particular.
Bill "losing proficiency with sanding block in hand" Watson
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
rampil
Joined: 04 May 2007
Posts: 870
|
| Posted: Thu Feb 18, 2010 2:02 pm Post subject: Re: Basic Electricity....Grrrrr......... |
|
|
Hey Bill,
Just remember that wax on - wax off with a sanding block generates
proficiency too (and muscles)!
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Ira N224XS |
|
| Back to top |
|
|
dave(at)coltnet.net
Guest
|
| Posted: Thu Feb 18, 2010 7:03 pm Post subject: Basic Electricity....Grrrrr......... |
|
|
| Quote: |
I've been rethinking the weekend seminar format as
a teaching tool. It's a drink-from-a-firehose which
probably has a lower rate of retention than a 3-hour
college course . . . which also has a demonstrably poor
retention rate.
|
Bob,
I would love to attend one of your seminars, but due to the distance,
work and a number of other
reasons of life getting in the way of life, I have been unable to
participate. Have you considered
a set of seminar dvds. Even though they seminars are a drink from the
firehose. The dvd/s could allow a review
as required and a chance for some of us to drink from the firehose who
may never get to drink in person.
Thanks for all of your contributions to the OBAM world.
Dave
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Thu Feb 18, 2010 7:11 pm Post subject: Basic Electricity....Grrrrr......... |
|
|
Good Evening Dave,
I was able to attend one of Bob's seminars near Milwaukee a couple of years ago. Well worth the time and if the opportunity presents itself. I will attend again.
Firehose or not, well worth the time!
Happy Skies,
Old Bob
In a message dated 2/18/2010 9:04:53 P.M. Central Standard Time, dave(at)coltnet.net writes:
| Quote: | --> AeroElectric-List message posted by: "Dave" <dave(at)coltnet.net>
| Quote: |
I've been rethinking the weekend seminar format as
a teaching tool. It's a drink-from-a-firehose which
probably has a lower rate of retention than a 3-hour
college course . . . which also has a demonstrably poor
retention rate.
|
Bob,
I would love to attend one of your seminars, but due to the distance,
work and a number of other
reasons of life getting in the way of life, I have been unable to
participate. Have you considered
a set of seminar dvds. Even though they seminars are a drink from the
firehose. The dvd/s could allow a review
as required and a chance for some of us to drink from the firehose who
may never get to drink in person.
Thanks for all of your contributions to the OBAM world.
Dave
| Quote: | ========================= Use utilities Day ================================================ - MATRONICS WEB FORUMS ================================================ - List Contribution Web Site sp; ===================================================
|
|
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
