Today's Message Index:
----------------------
1. 06:31 AM - Re: Ground plane diameter (Robert L. Nuckolls, III)
2. 07:17 AM - Re: Second big snow in a week! (Richard Girard)
3. 08:04 AM - Low EMI Noise Power Supplies (Eric M. Jones)
4. 08:24 AM - Re: Second big snow in a week! (Robert L. Nuckolls, III)
5. 08:39 AM - Re: Low EMI Noise Power Supplies (Robert L. Nuckolls, III)
6. 09:06 AM - Re: Ground plane diameter (R. curtis)
7. 09:14 AM - trouble with building Contactor 'Cooler' duty controller (Yahoo hasbroucka)
8. 09:35 AM - Re: Ground plane diameter (Robert L. Nuckolls, III)
9. 11:16 AM - Re: trouble with building Contactor 'Cooler' duty controller (Robert L. Nuckolls, III)
10. 12:34 PM - Re: trouble with building Contactor 'Cooler' duty controller (Yahoo hasbroucka)
11. 01:54 PM - Re: trouble with building Contactor 'Cooler' duty controller (Yahoo hasbroucka)
12. 02:31 PM - Re: Ground plane diameter (Paul Fisher)
13. 04:22 PM - Re: trouble with building Contactor 'Cooler' duty controller (Robert L. Nuckolls, III)
14. 04:26 PM - Re: Ground plane diameter (Robert L. Nuckolls, III)
15. 08:56 PM - Re: trouble with building Contactor 'Cooler' duty controller (Jan)
Message 1
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Subject: | Re: Ground plane diameter |
At 10:27 PM 2/25/2013, you wrote:
>OK, thanks Bob. It operates on 978 Mhz so I probably could have
>figured it out by breaking out my ARRL Antenna Book but I guess I
>was just a bit on the lazy side.
Very good. Yes, 978 MHz does work out to
a 6" diameter ground plane . . .
Bob . . .
Message 2
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Subject: | Re: Second big snow in a week! |
Winter Storm Rocky sat over Udall all night long. First time I've ever seen
lightning in the winter. We have six more inches but the winds have drifted
the road shut again. Oh well, I wasn't going anyplace anyway. Sure is
pretty outside, though.
Rick Girard
do not archive
On Mon, Feb 25, 2013 at 8:14 AM, Bill Bradburry <bbradburry@bellsouth.net>wrote:
> bbradburry@bellsouth.net>
>
> Darn! And pheasant season is over!
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert
> L.
> Nuckolls, III
> Sent: Monday, February 25, 2013 12:14 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Second big snow in a week!
>
> <nuckolls.bob@aeroelectric.com>
>
> Just got the drive cleared enough to get the
> truck out after a 12" snow on Friday, now
> they're calling for 16-20" again tomorrow.
>
> The only living thing really happy about all this
> is the wheat . . .
>
> They're not expecting freezing rain so maybe
> that new generator will still be in the box
> next week too. Dr. Dee got home last week before
> the snow and has just e-mailed all her students
> not to expect her tomorrow . . .
>
>
> Bob . . .
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 3
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Subject: | Low EMI Noise Power Supplies |
Here is a dyn-o-mite course on how to make low-noise power supplies. This is not
applicable to everyone, but the key point he discusses is that the PCB layout
is a key ingredient in making low noise designs.
http://cds.linear.com/docs/en/application-note/an139f.pdf
Why should you care? Because:
Stopping the EMI after you've caused it is the wrong (expensive!) way to go.
A power supply with noise is usually easier to avoid or replace or redesign than
filter and muffle. Making do with any-olde cheapo supply you find on Ebay or
Radio Shack will usually turn out to be the most expensive. Remember what Clique
and Claque say, "It's the stingey man who pays the most."
do not archive
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=395095#395095
Message 4
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Subject: | Re: Second big snow in a week! |
At 09:15 AM 2/26/2013, you wrote:
>Winter Storm Rocky sat over Udall all night long. First time I've
>ever seen lightning in the winter. We have six more inches but the
>winds have drifted the road shut again. Oh well, I wasn't going
>anyplace anyway. Sure is pretty outside, though.
We got off a lot easier than forecast. Only
9" instead of 20. Didn't get thundersnow with
this pass but did last week. Now, let's hope
for gentle melts that don't give us flooding!
There is hope for this year's wheat crop! It will
be interesting to see if any of those bare spots
in the fields will now germinate and catch up.
Being stuck inside shifted some efforts back
to the workbench. Paul has a good first-pass
on the software for the battery capacity
meter. I've got a bench battery tester here
that a List Reader built to the poor man's
cap tester article. I'm stripping out the
guts and rebuilding it with the micro-controller
based circuitry. Should be able to do a smoke
test this week.
The same device will be useful in the airplane
for orchestrating the occasional automatic
cap-test and recharge using the ship's established
e-bus loads. Introduction of this product will
remove all excuses for NOT knowing the capability
of the ship's battery.
Bob . . .
Message 5
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Subject: | Re: Low EMI Noise Power Supplies |
At 10:00 AM 2/26/2013, you wrote:
>
>Here is a dyn-o-mite course on how to make low-noise power supplies.
>This is not applicable to everyone, but the key point he discusses
>is that the PCB layout is a key ingredient in making low noise designs.
>
>http://cds.linear.com/docs/en/application-note/an139f.pdf
>
>Why should you care? Because:
>
>Stopping the EMI after you've caused it is the wrong (expensive!) way to go.
Exactly. HBC sent me to a Kimmle-Gerke seminar
some years ago.
http://tinyurl.com/b3ojtcp
Got to spend two days at the feet of Bill Kimmel hisself.
Most of the class time was expended on chasing horses
already escaped from the barn . . . because those situations
predominate in the wild. But a significant effort was
invested on keeping the barn doors shut tighter in the
first place. Much of what's offered in the application
note above was core to Bill's presentation.
The really cool thing about technology advances are
higher operating frequencies which give opportunity to
craft smaller devices (tighter geometry equals smaller
radiation apertures) and a reduction in the size of
components needed for attenuating conducted energies.
These are lessons learned that new kids on the block
would do well to explore. Unfortunately, much of what
we're trying to integrate into the uniquely demanding
arena of airplanes comes from less demanding markets.
Suppliers of those markets would much rather we did
not bolt their electro-whizzy to an airplane.
Increases in sales numbers are trivial and risks rise
exponentially.
For years, the best maker of v-belts in the world
specifically stated in their literature that their
products were institutionally unapproved for use
on airplanes . . . while boxes of said belts routinely
arrived in the warehouses at BePipCesMo.
It's a crazy world out there . . . and risks
for escaping gremlins to fiddle with your GPS
readings are not necessarily consistent with
either claims or disclaimers in the sales literature!
Bob . . .
Message 6
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Subject: | Re: Ground plane diameter |
>
> At 10:27 PM 2/25/2013, you wrote:
>>OK, thanks Bob. It operates on 978 Mhz so I probably could have
>>figured it out by breaking out my ARRL Antenna Book but I guess I
>>was just a bit on the lazy side.
>
> Very good. Yes, 978 MHz does work out to
> a 6" diameter ground plane . . .
I have seen often that antennas get cut off to tune
for maximum radiation. Is the ground plane as
critical in dimension as the radiating element?
Roger
--
Do you have a slow PC? Try a Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen
Message 7
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Subject: | trouble with building Contactor 'Cooler' duty controller |
I'm building a SeaRey Rotax 914, and am close on alternator amperage
output.
After reviewing archives I have now attempted to construct Bob's
'Contactor
Cooler'. I am very weak on electronics knowledge, but for the $20
investment, I gave it a shot.
I noticed that Caps come is different ratings and materials of
construction,
and for this stage of the experiment I decided to ignore this and simply
purchase the uf ratings as listed on the schematic. Do the voltage
ratings
or materials of construction matter to this device?
I finished assembly today, and noticed that I did not purchase any
iN400X
diodes (I assume the X could be any available #?) I recognized the 400X
as
voltage spike protection for avionics, so I decided to proceed without a
diode across the contactor coil.
The device worked for three cycles, about 5 seconds each, and simply no
longer operates the contactor. There was no smoke and no detectable
warmth.
I suspect that the missing diode allowed the coil V-spike to damage my
assembly?
If so, can anyone tell me which device is most likely to need
replacement?
(timer, transistor, diodes, resistors or caps) Not knowing much of
electronics, I only know how to test the resistors and diodes, but this
is
complicated by lack of isolation.
Alan ,
HasbrouckA@yahoo.com
SeaRey Amphibian, framework and hull assembled (not covered). Working on
VFR
avionics and wiring (Dynon Skyview full suite). Top Priority is keep it
light, and place weight forward!
Message 8
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Subject: | Re: Ground plane diameter |
>
> I have seen often that antennas get cut off to tune
> for maximum radiation. Is the ground plane as
> critical in dimension as the radiating element?
>
> Roger
I guess it depends on your threshold for assigning
criticality. I've spent hours in the labs watching
displays on instruments that dutifully reported
measurable differences. It's really EASY . . . especially
for designers and technicians to work in relative
isolation from practical results to take lots
of pride and assign criticality to small
improvements.
Improvements in the lab go to statistical process
control. LOTS of tiny improvements in the bits
and pieces can add up to significance improvements
in the full up system. At the same time, the guy
who is fine-tuning his little bit has no control
over how it will be installed nor will he control
less than optimum outcomes for associated bits.
In the world of antennas, the observable effects
for fabrication are greatest in management
of radiation pattern. I've seen some plots on
airframe mounted antennas with deep nulls in
azimuth plots. Careful tuning for resonance
is the least part of the recipe for success.
I.e., optimized SWR and field strength numbers
can be misleading.
http://tinyurl.com/bea4785
Bottom line is that taking time to 'trim' a
ground plan is probably the least productive
effort. Fortunately, the very short UHF monopole
antennas are pretty easy to locate to minimize
airframe distortions of pattern. We are further
aided by the fact that terrible losses can be
tolerated in the world of relatively short
range, line of sight world for aircraft
communications.
The only airplanes we ever studied for antenna
radiation patterns were the big guys who flew
routinely over water at 41,000 feet with very
distant radio-horizons. The only pattern work
I ever witnessed on a small airplane was done
by Dr. Gordon Wood on a C-172 at Cessna about 1963.
I don't think the outcome of those studies
prompted any changes to our legacy installations.
Don't worry about the ground plane . . .
Bob . . .
Message 9
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Subject: | Re: trouble with building Contactor 'Cooler' duty |
controller
At 11:12 AM 2/26/2013, you wrote:
>I'm building a SeaRey Rotax 914, and am close on alternator amperage
>output. After reviewing archives I have now attempted to construct
>Bob's 'Contactor Cooler'. I am very weak on electronics knowledge,
>but for the $20 investment, I gave it a shot.
>
>I noticed that Caps come is different ratings and materials of
>construction, and for this stage of the experiment I decided to
>ignore this and simply purchase the uf ratings as listed on the
>schematic. Do the voltage ratings or materials of construction
>matter to this device?
Not especially. Anything over 12v works.
>
>I finished assembly today, and noticed that I did not purchase any
>iN400X diodes (I assume the X could be any available #?) I
>recognized the 400X as voltage spike protection for avionics, so I
>decided to proceed without a diode across the contactor coil.
No, the 'x' means don't care. Any number from
0 to 9 is suited to the task.
>
>The device worked for three cycles, about 5 seconds each, and simply
>no longer operates the contactor. There was no smoke and no detectable warmth.
>
>I suspect that the missing diode allowed the coil V-spike to damage
>my assembly?
That's a fair assumption. What does the contactor do?
If your IRF510 is shorted, the contactor will simply
pull in at full voltage. I suspect that this is what's
happening. Give us a voltage measurement on your contactor
coil when the device is powered up. Also a voltage
measurement at pin 3 of the 555 say 10 seconds after
the device is powered up.
>
>If so, can anyone tell me which device is most likely to need
>replacement? (timer, transistor, diodes, resistors or caps) Not
>knowing much of electronics, I only know how to test the resistors
>and diodes, but this is complicated by lack of isolation.
As Lord Kelvin opined many years ago:
"When you can measure what you are speaking about, and express it in
numbers, you know something about it, when you cannot express it in
numbers, your knowledge is of a meager and unsatisfactory kind; it
may be the beginning of knowledge, but you have scarcely, in your
thoughts advanced to the stage of science."
Let's get the numbers. By the way, thanks
for taking this project on. Let's make sure
the outcome expands your knowledge and the
utility of your airplane.
Bob . . .
Message 10
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Subject: | trouble with building Contactor 'Cooler' duty |
controller
The contactor no longer does anything when wired thru the device, but it
works fine without the device.
V across coil is 0
V at pin 5 after 10 sec. is 11.9 (supply V is 12.7)
Alan ,
HasbrouckA@yahoo.com
SeaRey Amphibian, framework and hull assembled (not covered). Working on
VFR
avionics and wiring (Dynon Skyview full suite). Top Priority is keep it
light, and place weight forward!
The device worked for three cycles, about 5 seconds each, and simply no
longer operates the contactor. There was no smoke and no detectable
warmth.
I suspect that the missing diode allowed the coil V-spike to damage my
assembly?
That's a fair assumption. What does the contactor do?
If your IRF510 is shorted, the contactor will simply
pull in at full voltage. I suspect that this is what's
happening. Give us a voltage measurement on your contactor
coil when the device is powered up. Also a voltage
measurement at pin 3 of the 555 say 10 seconds after
the device is powered up.
If so, can anyone tell me which device is most likely to need
replacement?
(timer, transistor, diodes, resistors or caps) Not knowing much of
electronics, I only know how to test the resistors and diodes, but this
is
complicated by lack of isolation.
Message 11
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Subject: | trouble with building Contactor 'Cooler' duty |
controller
Alan ,
HasbrouckA@yahoo.com
SeaRey Amphibian, framework and hull assembled (not covered). Working on
VFR
avionics and wiring (Dynon Skyview full suite). Top Priority is keep it
light, and place weight forward!
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Yahoo
hasbroucka
Sent: Tuesday, February 26, 2013 3:31 PM
Subject: RE: AeroElectric-List: trouble with building Contactor 'Cooler'
duty controller
The contactor no longer does anything when wired thru the device, but it
works fine without the device.
V across coil is 0
V at pin 5 after 10 sec. is 11.9 (supply V is 12.7)
[Alan Hasbrouck] V at pin 3 after 10 sec. is .01V
Alan ,
HasbrouckA@yahoo.com
SeaRey Amphibian, framework and hull assembled (not covered). Working on
VFR
avionics and wiring (Dynon Skyview full suite). Top Priority is keep it
light, and place weight forward!
The device worked for three cycles, about 5 seconds each, and simply no
longer operates the contactor. There was no smoke and no detectable
warmth.
I suspect that the missing diode allowed the coil V-spike to damage my
assembly?
That's a fair assumption. What does the contactor do?
If your IRF510 is shorted, the contactor will simply
pull in at full voltage. I suspect that this is what's
happening. Give us a voltage measurement on your contactor
coil when the device is powered up. Also a voltage
measurement at pin 3 of the 555 say 10 seconds after
the device is powered up.
If so, can anyone tell me which device is most likely to need
replacement?
(timer, transistor, diodes, resistors or caps) Not knowing much of
electronics, I only know how to test the resistors and diodes, but this
is
complicated by lack of isolation.
Message 12
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Subject: | Re: Ground plane diameter |
It might seem lazy on your part just to get a number - but some of us got
an education on WHY that was the number. So thanks for asking!
(and of course Thank You Bob for the explanation!)
- Paul
On Feb 25, 2013 10:44 PM, "William Hibbing" <n744bh@bellsouth.net> wrote:
> OK, thanks Bob. It operates on 978 Mhz so I probably could have figured
> it out by breaking out my ARRL Antenna Book but I guess I was just a bit
> on the lazy side.
>
> Bill
>
> ------------------------------
> *From:* "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
> *To:* aeroelectric-list@matronics.com
> *Sent:* Mon, February 25, 2013 8:06:58 PM
> *Subject:* Re: AeroElectric-List: Ground plane diameter
>
> At 03:30 PM 2/25/2013, you wrote:
>
> I'm upgrading avionics in my Glasair and one of the units I'm adding is a
> Garmin GDL-88 for ADS-B out. The antenna I'm using is a Comant CI-105 and
> seeing it's a "plastic" airplane I've been wondering if a 6" diameter
> copper disc is large enough for the ground plane or should I go a bit
> larger? TIA
>
>
> To understand the workings of ground planes under
> vertical 1/4-wave radiators (like comm, transponder
> and DME) antennas, you need to take a little 'head
> trip'.
>
> The older brother to a 1/4-wave antenna fed at the
> base is a 1/2-wave antenna fed at the center (aka
> VOR/LOC/GS atennas). The 1/2 wave antenna doesn't
> need a 'ground' because is has useful places to send
> 1/2 of the total energy into each of two identical,
> complimentary radiators.
>
> Now, take a dipole and turn it up vertically as if
> you wanted to use it for comm. Hmmmm . . . hard to
> attach the coax to it while insulating the hot
> end of the lower element. Okay, bend the lower element
> 90 degrees. Now the feed point at the antenna
> center comes down to skin level on the airplane . . .
> but the 'bent' half of the antenna is seriously
> compromised for efficiency as it no longer works
> in concert with its unmodified counterpart.
>
> Hmmmm . . . how to make the lion's share of the energy
> flow into the freely extended portion of the antenna
> while reducing a wasteful venture onto the
> compromised portion of the antenna? How about adding
> a second compromised element? Assume the feed point
> impedance of each element is R. Then a dipole in
> extended splendor has a feed point impedance of 2R.
>
> You've still got R + R with the compromised dipole
> but paralleling two 'crippled' elements at the base
> gives you 1/2R + R. We see that energy fed to
> this network divides with 1/3 going to the compromised
> side and 2/3 to the free element. Let's consider adding
> 2 more 'compromised' elements. Now we have 1/4R + R.
> Great! 4/5ths of the energy goes to the working part
> while only 1/5th is left free to roam and be a general
> nuisance to your radiation pattern.
>
> Now, if you want to squirt your signal off at an
> angle that is closer to the horizon, you can droop
> those elements not unlike the antennas seen around
> many airports.
>
>
> [image: http://www.krecoantennas.com/images/gp-155.jpg]
>
> Take this exercise to an extreme . . . say 100
> 'compromised' elements. Now you get 1/100R + R
> and only 1% of the energy is left free to be
> problematic. Further, 100 compromised elements
> look very close to a solid disk of material having
> a RADIUS equal to the HEIGHT of the free element.
> You sometimes see 100 drooping elements that look
> very much like a cone of solid metal.
>
> So, getting back to your question, the IDEAL small
> ground plane has a radius equal to the 1/4-wave
> distance for the frequency of interest. In the case
> of transponders, this works out to 300M meters/sec
> divided by 1050 cycles/second times 39.36 inches/meter
> times 0.25 wavelength and you get 2.8 inches. Twice
> this value is 5.6", the ideal resonant ground plane
> for transponder antennas.
>
> Making it just a little bigger because you can is
> counter productive. On the other hand, making it
> MUCH bigger (like the belly of a metal airplane)
> and it begins to approximate a non-resonant, infinite
> ground plane which is very good too . . . but a
> a whole different ballgame.
>
> The short answer is that for a non-conducting
> mounting surface the antenna performs best with
> the idealized, 1/4-wave radius disk. If you
> could mount it to several square feet of aluminum
> it would only slightly better . . . so slight
> that you would need to measure the difference
> in a well heeled RF lab. So the best recommendation
> is go for the 5.6" disk.
>
> Bob . . .
>
> *http://www.matronics.com/Navigatrums.matronics.com/" rel=nofollow target=_blank>http://forums.matronics-> <http://www.matronics.com/contribution>*
>
> *
>
> *
>
>
Message 13
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Subject: | trouble with building Contactor 'Cooler' duty |
controller
At 02:31 PM 2/26/2013, you wrote:
>The contactor no longer does anything when wired thru the device,
>but it works fine without the device.
>
>V across coil is 0
>V at pin 5 after 10 sec. is 11.9 (supply V is 12.7)
No, need the voltage at pin 3 . . . we need to
know if the critter is dropping into low duty
cycle.
You should see about 12v for a period of time
and then it should drop to 4 volts or so.
Bob . . .
Message 14
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Subject: | Re: Ground plane diameter |
At 04:30 PM 2/26/2013, you wrote:
>It might seem lazy on your part just to get a number
>- but some of us got an education on WHY that was the
>number. So thanks for asking!
>
>(and of course Thank You Bob for the explanation!)
>
>- Paul
My pleasure sir. I know some folks may feel
a bit over-informed but I'll ask that they
keep in mind that this list has about 1600
subscribers (at last count 6 months ago).
Interest in answers has to span a wide
range and I try to address it.
Not trying to preach or 'stuff' anyone
with data they don't wish to possess . . .
Bob . . .
Message 15
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Subject: | Re: trouble with building Contactor 'Cooler' duty |
controller
What is the link to the circuit please - I have been looking on your web sit
e but not able to find it
All the best
Jan
On Feb 27, 2013, at 3:06, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectr
ic.com> wrote:
> At 11:12 AM 2/26/2013, you wrote:
>> I?m building a SeaRey Rotax 914, and am close on alternator amperage outp
ut. After reviewing archives I have now attempted to construct Bob?s ?Contac
tor Cooler?. I am very weak on electronics knowledge, but for the $20 invest
ment, I gave it a shot.
>>
>> I noticed that Caps come is different ratings and materials of constructi
on, and for this stage of the experiment I decided to ignore this and simply
purchase the uf ratings as listed on the schematic. Do the voltage ratings o
r materials of construction matter to this device?
>
> Not especially. Anything over 12v works.
>>
>> I finished assembly today, and noticed that I did not purchase any iN400X
diodes (I assume the X could be any available #?) I recognized the 400X as v
oltage spike protection for avionics, so I decided to proceed without a diod
e across the contactor coil.
>
> No, the 'x' means don't care. Any number from
> 0 to 9 is suited to the task.
>>
>> The device worked for three cycles, about 5 seconds each, and simply no l
onger operates the contactor. There was no smoke and no detectable warmth.
>>
>> I suspect that the missing diode allowed the coil V-spike to damage my as
sembly?
>
> That's a fair assumption. What does the contactor do?
> If your IRF510 is shorted, the contactor will simply
> pull in at full voltage. I suspect that this is what's
> happening. Give us a voltage measurement on your contactor
> coil when the device is powered up. Also a voltage
> measurement at pin 3 of the 555 say 10 seconds after
> the device is powered up.
>
>>
>> If so, can anyone tell me which device is most likely to need replacement
? (timer, transistor, diodes, resistors or caps) Not knowing much of electro
nics, I only know how to test the resistors and diodes, but this is complica
ted by lack of isolation.
>
> As Lord Kelvin opined many years ago:
> ?When you can measure what you are speaking about, and express it in numbe
rs, you know something about it, when you cannot express it in numbers, your
knowledge is of a meager and unsatisfactory kind; it may be the beginning o
f knowledge, but you have scarcely, in your thoughts advanced to the stage o
f science.?
>
> Let's get the numbers. By the way, thanks
> for taking this project on. Let's make sure
> the outcome expands your knowledge and the
> utility of your airplane.
>
>
>
> Bob . . .
>
>
>
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