Science and Technology news... :: View topic - Surge protectors to use with home electronics when grounding

John Fields · Guest

On Mon, 30 Jun 2008 12:09:51 -0700 (PDT), w_tom <w_tom1@usa.net>
wrote:

[quote]On Jun 29, 8:43 pm, John Fields <jfie...@austininstruments.com> wrote:
Nothing of any consequence.

So John, where is any professional citation that says characteristic
impedance is relevant? Nothing.

Where is this professional citation that says common mode surges -
what lightning creates - are not typically destructive surges?
Nothing.

Where is this professional citation that says a hot to neutral surge
is not eliminated (reduced) by that same one 'whole house' protector?
Nothing.

Why is a peer reviewed front page article in a highly regarded
electrical engineering publication not relevant? Its title:
"Protecting Electrical Devices from Lightning Transients". John
somehow knows industry professionals are wrong?

You have even confused characteristic impedance with wire impedance.
Why do you ignore wire impedance and discuss irrelevant wire
resistance? Your denials are based only in insults?

Why does every telco install 'whole house' protectors and not waste
money on plug-in protectors? For better protection, why do telcos
locate protectors distant from electronics - up to 50 meters? For
better protection, why do telcos install even better earthing and
connect 'whole house' protectors as short as practicable to that
earthing? John says telcos are also loony?

And where is that plug-in protector spec that claims protection?
Oh. No plug-in protector will list protection from each type of
surge. But you know that plug-in protector is effective?

Where does John Fields post a solution for the OP whose building
only has two wire receptacles? You provide no useful answers.

OP>s solution is simple, more effective, and less expensive than
plug-in protectors. Similar to a solution implemented by all telcos,
commercial broadcasters, rocket launch facilities, and military
bases. A 'whole house' protector with breaker box earthing is
upgraded to post 1990 National Electrical Code standards. Complete
surge protection installed for about $1 per protected appliance.

Why does John Fields recommend using three wire power strip
protectors on two wire receptacles? How do John>s insults prove
science or assist the OP? John even denies lightning creates common
mode surges. A protector is only as effective as its earth ground as
noted by numerous above and responsible sources. Meanwhile, the OP
cannot use plug-in protectors. His best solution is the standard
solution used everywhere when surge damage is not acceptable.
[/quote]
---
Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-based surge suppressors can be used to good
advantage in premises without (or with unused) earth grounding.

That is, after all, the topic as indicated by the subject line.

If you>d like to discuss whole-house surge protection I suggest you
start another thread with a subject which reflects that topic

I also realize from your questions (which you pose as sarcastic
challenges) that you don>t understand the subject matter involved and
hope that I>ll "vindicate" myself by coming back with answers which
you can then study up on and pretend you knew them all along, as
you>ve done with "common mode" and "characteristic impedance".

Sorry, Charlie, I don>t play that way.

JF

Michael A. Terrell · Guest

w_tom wrote:
[quote]
On Jun 29, 8:43 pm, John Fields <jfie...@austininstruments.com> wrote:
Nothing of any consequence.

So John,
[/quote]

Give it a rest. You aren>t fooling anyone, You have never had anyone
agree with any of your lies or idiocy, so go away.

--
http://improve-usenet.org/index.html

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

Sporadic E is the Earth>s aluminum foil beanie for the 'global warming'
sheep.

Tim Wescott · Guest

steamer wrote:
[quote] --Oops followup question: the sequencer output is around 400hz AC;
will this cause any problems with a relay?

Probably, unless it>s specially designed for 400Hz; if there were such a[/quote]
beast it would be a specialized aircraft relay from the 60>s or 70>s.

You could rectify the AC with a little bridge and use that to feed the
relay -- it should work well. Just what you need for a rectifier and
associated circuitry depends on whether the relay you use is mechanical
or not. For a mechanical relay there>s a good chance that you could
just use a bridge and count on the relay coil>s inductance to smooth the
current out sufficiently; for a solid-state relay you>d probably need a
bridge, filter capacitor and loading resistance.

--

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

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

steamer · Guest

--Oops followup question: the sequencer output is around 400hz AC;
will this cause any problems with a relay?

--
"Steamboat Ed" Haas : "Hold on! we>re passing
Hacking the Trailing Edge! : through the moronosphere!"
www.nmpproducts.com
---Decks a-wash in a sea of words---

Kris Krieger · Guest

ehsjr <e.h.s.j.r.removethespampunctuation@bellatlantic.net> wrote in
news:rfd9k.9$dz.4@trndny01:

[quote]Kris Krieger wrote:
ehsjr <e.h.s.j.r.removethespampunctuation@bellatlantic.net> wrote in
news:8vU8k.58$BR.4@trnddc06:

Kris Krieger wrote:

ehsjr <e.h.s.j.r.removethespampunctuation@bellatlantic.net> wrote in
news:u3E8k.54$WJ.12@trnddc04:

[edited]

Only *after* I know all that, can I select the specific cells, and
configuration therof...

- Kris

As you said, you are working backwards. You don>t yet understand
that doing it that way can result in a specification for cells
that are "unobtanium".

Ed

"Unobtanium"??, it>s a modest LED night-lamp, not an airport beacon
:p

I *already* know the batteries and their output, and the input needed
by the LED driver and what it will output to run the LEDs (which will
run off the batteries at night) - those are not the problem.

To charge my 4 little 1.2V AA NiMH batteries, I have seen the
following solar cells (and more, this isn>t an all-inclusive list):
0.5V, 200mA
0.5V, 450mA
0.5V, 800mA
0.5V, 2000mA
1V, 200mA
2V, 200mA
3V, 400mA
4V, 25mA
etc.

I also know that, depending upon how I connect cells, I can up the
Volts or up the Amps, or both if it>s a series-parellel combination.
The biggest Q. is the volts. I read that, using a 5V solar cell,
charging time would be the battery mA divided by the cell mA, but
what if it was a 2V cell, or a .5V cell?

Well, I>ll write to Maxim, since it>s their components I>m interested
in. They can prob. best tell me the input I need for the
battery-management IC.

- Kris

Sorry, Kris, but in terms of the necessary specifications,
you have posted nothing useful to make an informed design
decision. That is not an attack on you, it is just that
you are working in an area that is new to you.
[/quote]
I found teh answer to my question here:
http://www.solar-world.com/SolarMini-Panels&Motors.htm

Specifically:
"...the solar operating voltage must be higher than the battery voltage..."

That was all I was asking.

[quote]Netting your problem out, you want to drive an unknown
(in terms of voltage and current) load
[/quote]
The Q was not about the "load", it was *simply* and *specifically*, I>ll
repeat, this:
Given NiMH batteries, size AA, rated at 1.2V and 1500mA, what would I need
in terms of soalr cell output to charge tem using a battery
charge/control/protection IC (the Maxim DS2715).

I don>t understand what in that is "unknown" or otherwise unspecific.

[quote]for an unknown amount
of time with an unknown number (but less than 5)
[/quote]
I>d repeatedly specified "between 3 and 4"...

[quote]NiMh AA
cells of unknown capacity, said NiMh>s to be charged with an
unknown number of solar cells of unknown capacity in an
unknown environment.
[/quote]
*Of course* the number of solar cells was unknown - anyway, the "number" is
not relevant, what is relevant is the *output*, and my Q. was specifically
about *needed output*, so that I could go back to the catalogues, look at
the sizes/ratings, and determine what I>d need in terms of numbers, and
arrangements.

As for environment, not relevant to teh question - the question dealt with
ratings. I>m not so stupid that I think SOLAR cells will "work" at night
or in deep shade, or that they generate the same power on cloudy days as on
bright, sunny days. But I did not ask about differnces in output on cloudy
versus sunny days, I asked, based purely upon ratings, about charging a
specifically-described battery.

[quote]
The key design question is: how much input power will be
available?
[/quote]
No, the key design question was, as Tom Biasi had notd when I first began
asking my Solar Light questions, was:
"One place to start would be to determine how much illumination you need.
Find LEDs that can give you that. What voltage and current do you need to
power the LEDs for the period of time that you would like? What battery
will provide that?"

The question I asked in this thread was the final question of Tom>s initial
input:
"What solar arrangement can charge the battery in the time that you want?"

I didn>t know how to do the math. Now I think I might know it.

[quote]The surface area of your device that will
be exposed to direct sunlight and that you are willing to
dedicate to solar cells will determine that, in terms of
the maximum that can be achieved.
[/quote]
THat wasn>t what I was asking. I was asking what output (from the cells)
I>d need to charge the specified batteries. I didn>t ask about sruface
area - I alreasy knew that, which is why I listed several of the available
solar cell outputs, which I>d selected becasue their footprint fell within
the size limits I wanted. So the surface area was not the concern and was
not at all related to the simple question I was asking.

[quote]Obviously, the power
will be less if the device is in the shade or the cells
receive less than full sunlight for some other reason.
[/quote]
Not to be rude, but, duuuuuuuuh... Again, tho', not what I was asking.

[quote]
You are here asking for help - but _ONLY_ you can answer
that question.
[/quote]
Well, between all the different solar-cell-related websites, electronics-
related websites, the Tech Support folk at Maxim, and so on, yeah, you>re
right, I finally *am* answering the question I>d asked in this thread about
what Solar Cell output is required to charge the specified batteries.

[quote]
If we don>t know how much power is available, it is not
possible to say definitively if your idea is even feasible,
let alone specify how to do it.

[/quote]
You can>t figure out whether it>s feasible to run 4 regular (i.e. discrete
5mm dome) LEDs off of a solar-charged battery pack of 3 NiMH AA 1500mA
batteries?, or up to 6 (same type) LEDs off a solar-charged battery pack of
3 or 4 NiMH AA 1500mA batteries?, or what output V and mA you>d need from
solar cells (obviously placed in the sun :p ) to charge even one
1.2V/1500mA NiMH battery? You can>t even determine whether that is
*possible*?

OK, whatever...

Thankfully, there were a couple of folks who were very helpful and got me
going in the right direction, whom I>m thanking in a separate post.

- Kris

w_tom · Guest

On Jun 30, 4:06 pm, John Fields <jfie...@austininstruments.com> wrote:
[quote]Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-basedsurgesuppressors can be used to good
advantage in premises without (or with unused) earth grounding.
That is, after all, the topic as indicated by the subject line.
[/quote]
Every responsible source says the grounding must exist. No surge
protection stops or absorbs the common mode surge - surge that
typically causes appliance damage. As Bud>s NIST states:
[quote]... your surge protector will work by diverting the
surges to ground. The best surge protection in the
world can be useless if grounding is not done
properly.
[/quote]
*Diverting*. Your ASCII protector has all but no earth ground.
Excessive wire impedance. Nothing to divert to. Protector is the same
problem demonstrated in Bud>s other citation. Page 42 Figure 8 - a
protector too far from earth ground and too close to appliances
therefore leaves surge energy earthed 8000 volts destructivley through
an adjacent TV.

No way around what a protector does. Either it stops (absorbs)
surge energy OR is diverts (shunts, connects, clamps) that surge
energy into earth. A destructive surge will increase voltage. as
necessary, to connect to earth - Page 42 Figure 8. Stopping
(absorbing) surge energy is not effective protection. Your ASCII
circuit protector with excessive wire impedance must absorb all surge
energy (impossible) or divert a surge destructively via household
appliances - Page 42 Figure 8.

The OP need not rewire the house. But no way around what provides
effective protection. As every responsible source notes, that service
entrance earth ground must exist for the same reasons earthing exists
in every telco facility. One 'whole house' protector means everything
is protected. Protection that your ASCII circuit does not provide.

As even Sun Microsystems notes in their Planning guide for Sun
Server room:
[quote]Section 6.4.7 Lightning Protection:
Lightning surges cannot be stopped, but they can be diverted.
The plans for the data center should be thoroughly reviewed
to identify any paths for surge entry into the data center.
Surge arrestors can be designed into the system to help
mitigate the potential for lightning damage within the data
center. These should divert the power of the surge by providing
a path to ground for the surge energy.
[/quote]
Who should the OP believe? John Fields? Or Sun Microsystems ...
and the IEEE, NIST, US Air Force, QST (the ARRL), Dr Kenneth
Schneider, Electrical Engineering Times, Schmidt Consulting,
Polyphaser>s highly regarded application notes, a station engineer
from WXIA-TV, ...
[quote]Effective protectors work by earthing surges. That wall receptacle
wire is woefully too long, has sharp bends, had splices, is bundled
with other wires, etc. Each point conspires to make it only a safety
ground (equipment ground) and not earth ground.
[/quote]
Even Martzloff describes what would happen with your ASCII circuit:
[quote]Conclusion
1) Quantitative measurements in the Upside-Down house clearly
show objectionable difference in reference voltages. These occur
even when or perhaps because, surge protective devices are
present at the point of connection of appliances.
[/quote]
An MOV protects by becoming more conductive? What happens when a
surge protector has even higher joules numbers? Then the protector
absorbs even less surge energy. A better protector (higher joules)
absorbs less surge energy - what is desirable. MOVs don>t protect by
absorbing surges - which is why a Wikipedia citation on joules was
irrelevant. MOVs protect by diverting energy elsewhere - earth
ground.

John do you really believe a hundred joules in a UPS or power strip
will stop (by absorbing) lightning energy? Do you know how tiny 200
joules is? Where is protection from a 200 joule MOV?

Both wire and MOVs absorb some energy while shunted massive energy
elsewhere. A 200 joule protector is expected to shunt maybe 2000 or
50,000 joules into earth (20,000 amps) Whereas the MOV may absorb 200
joules, earth must dissipate thousands of joules. Better protectors
work more like wires - shunting more energy while dissipating even
less - or why your Wikipedia citation makes no sense.

What is wrong with ASCII diagrams? First, you promote wire
resistance that is irrelevant. Your 14 AWG wire at 0.15 ohms
resistance is also something like 130 ohms impedance. (Not
characteristic impedance with is something completely different).

Second, your 1000 volts surge at a transformer is made completely
irrelevant by protection required inside all computers. All computers
are required to withstand 1000 volt transients. Many have internal
protection that means even higher voltages without damage. That
transformer surge voltage will be lower at appliances. No problem.
Electronics routinely withstand 600 volt transients without damage - a
standard from 1970.

Third, surges are current events - not voltage. Tiny surges are 100
amps (not 8 amps). Serious surges are thousands of amps. Effective
'whole house' protectors must earth tens of thousands of amps so that
voltages at all appliances remain below 600 volts. Again, why high
reliable facilities use 'whole house' protectors and don>t use your
point of use protection.

Fourth, any attempt to stop or absorb surge energy means voltages
rise as much as necessary to blow through that blockage. Voltage will
rise as high as necessary to connect that current to earth. Lightning
makes the most non-conductive material (air) into miles of conductor.
Nothing stops (absorbs) the typically destructive surge that seeks
earth ground. Effective protection *diverts* surges to earth on non-
destructive paths. Which does your ASCII protector do? Divert that
energy into earth or absorb it. Which one? Surge protection is about
earthing (diverting) before surge energy can enter a building.

Fifth, if a designer who used MOVs, then you would have accurate
numbers. One milliamp through your 150v MOV puts it at just above
200 volts. Your 150 volt MOV does not conduct at 150 volts. Serious
surge currents start with the 150 volt MOV at around 300 volts. John
Fields - your ASCII circuit description violates every number in this
paragraph. No MOV is installed to keep appliance voltage at 150 volts
as you posted. You would know that had you designed protectors and
studied V-I charts for MOVs. You don>t even know how MOVs work.

Sixth - clamping the hot and neutral wire means surge energy remains
on both wires - unclamped - still seeking earth ground. Assume all 8
amps of a near zero (non-destructive) surge used the neutral wire to
obtain earth: that protector is at maybe 540 volts (not 150 volts).
A nondestructive surge because an 8 amp surge is too trivial to
overwhelm protection typically in all electronics. Your circuit only
works for a type of surge that typically does not do damage AND fails
- provides no protection - for the type of surge that does cause
appliance damage. A destructive surge means energy remains on that
hot and neutral wire, still seeking earth ground, and maybe finding
earth 8000 volts destructively via some appliance. Page 42 Figure 8
demonstrates this.

Your ASCII circuit protects from a surge (measured in voltage) that
is not destructive, has trivial energy, made further irrelevant by one
'whole house' protector, and that does not represent what effective
protectors are designed to eliminate. Destructive surges are not a
trivial 8 amps and defined by wire resistance. Your 150v MOV does not
clamp at 150 volts. Your example even demonstrates no knowledge of
MOV datasheets. Numerous additional technical problems with your
ASCII circuit. John - you don>t even know the V-I curves for MOVs.
You have never designed this stuff let alone test it.

Why do telcos not use your ASCII circuit? Telcos have the exact
same surge problem AND must never suffer surge damage. Same problem
and solution applies to every high reliability facility. To avoid how
surge protection works, you simply pretend telcos don>t suffer
surges? Nonsense. I designed this stuff that was tested by direct
lightning strikes. You clearly never did design (as demonstrated by
your 150v MOV conducting current at 150 volts). Protection now
required in every home is how ham radio operators did it 80 years ago.
Your protection circuit violated what hams knew 80 years ago.

What you should have known. That 150v MOV has 150 volts across it
when conducting how much current? Less than 1 milliamp. Why did you
not know what every protector designer would know? Take a 200 joule
MOV (V151CA32). What is that 150v MOV voltage when conducting an 8
amp surge? About 360 volts (not 150 volts). Why am I quoting from a
V-I chart that you clearly never read? How do you know what that MOV
does when you assume rather than read datasheets? That is the point.
Worse. John - you still discuss what is irrelevant (wire resistance)
and ignore what responsible engineering sources discuss (wire
impedance).

How critical is wire impedance? Manufacturers even define wire
impedance in that two inch MOV lead for test purposes. Where a tester
connects to an MOV>s leads changes MOV electrical responses. Why?
Wire impedance (not wire resistance) is important even in manufacturer
application notes. To post accurately, John would also know this:
[quote]Varistors: Ideal Solution to Surge Protection by Bruno van Beneden
In conventional leaded devices, the inductance of the lead
can slow the fast action of the varistor to the extent that
protection is negated.
[/quote]
Just another source that demonstrates wire impedance - not resistance
- for protection. Even inductance in MOV wire leads can degrade
protection because impedance (not resistance) is the critical
parameter.

John, your ASCII circuit cites wire resistance which is irrelevant
(as so many sources state) AND demonstrates design ignorance of how
MOVs work. You don>t even know MOV voltage when conducting a trivial
8 amps. Glaring, obvious, and unacceptable mistakes in your ASCII
circuit. A mistake that exists due to no protector design experience.

Protection is about earthing. The effective protector must make a
short (low impedance) connection to earth - as every responsible
source says and John denies. Voltages between wires is trivial.
Voltages (and more important - current) between each wire and earth
defines surge protection. One effective protector means earthing even
ten thousand amps to earth - without damage.

John - I only listed simplest mistakes in your ASCII protector
circuit. More exist. But you don>t even know the most basic numbers
or a V-I chart for MOVs. You still confuse irrelevant resistance with
what so many other sources discuss? Wire impedance.

Why do sharp bends cause further compromise surge protection? Sharp
bends don>t affect wire resistance and increases wire impedance. So
why do you still discuss resistance?

Guest · Posted: Tue Jul 01, 2008 7:24 am Post subject: Re: Vacuum Tube 6EJ7 Test

I had a little more time to look at the circuit today and make some
measurements. I reset the plate and screen grid to 200 vdc. I varied the
g1 voltage from -5 to -2.4 and recorded Ib at normal levels. Ic2 also
seemed normal. I have g1 connected to cathode through the 10k resistor. I
need to look at a few more things as I am told that these tubes were not
outputting up to spec. I can>t recreate the circuit they were used in so
I>m just doing the best I can to verify they have low output. So far they
seem ok. Any thoughts?

Thanks,
Don

MikeWhy · Guest

I realize it>s an old conversation, but...

What>s involved in building a simple 50 MHz oscilloscope? I have a spare
Xilinx Spartan DSP board, and an unused LTC 105 MSps A/D chip in the part
box. The board>s 125 MHz clock is different enough from the sampling rate, I
think, to jitter the trigger point for meaningful averaging. It seems almost
too simple. Aside from a low noise amp, what am I missing? The board has a
VGA port, 128 MB 5ns DDR2, and tons of I/O.

"David L. Jones" <altzone@gmail.com> wrote in message
news:485dfbd6$1@dnews.tpgi.com.au...
[quote]
"Talal Itani" <titani@verizon.net> wrote in message
news:6zk7k.871$9J.437@trnddc06...

One model that I have used is this one:
http://www.dynoninstruments.com/products_elab080.php
It>s a DSO, logic analyzer, and waveform generator all in one.
It>s only 80 MS/s but for $500 you can>t expect much more. I>ve actually
found
myself using the digital waveform generators on this thing quite often.

Thanks, this is nice, yet I wished it had a higher sampling rate. Are
you aware of any others?

Most low to medium end PC based DSO>s are all a similar sample rate, i.e.
a few hundred MHz.
Because they all use off-the-shelf FPGA>s and memories in their design,
and that>s about as high as you can go cheaply.
When you start talking 1GS/s+ you are into the high end domain of the big
manufacturers of professional oscolloscopes.

Agilent make a PC based DSO that might suit you if you *really* want a PC
based scope:
http://www.home.agilent.com/agilent/product.jspx?nid=-536902447.774929.00&cc=US&lc=eng
200MHz, 1GS/s, 32Mpoint memory, $1600

Stop being cheap, you *need* at least one real bench scope for your lab,
even if it>s a lower end mixed signal scope like a Rigol:
http://cgi.ebay.com.au/RIGOL-DIGITAL-Oscilloscope-DS1102CD-100M-COLOUR-LCD_W0QQitemZ150261816918QQihZ005QQcategoryZ45008QQrdZ1QQssPageNameZWD2VQQcmdZViewItem

Dave.
[/quote]

Jim Granville · Guest

MikeWhy wrote:
[quote]I realize it>s an old conversation, but...

What>s involved in building a simple 50 MHz oscilloscope? I have a spare
Xilinx Spartan DSP board, and an unused LTC 105 MSps A/D chip in the
part box. The board>s 125 MHz clock is different enough from the
sampling rate, I think, to jitter the trigger point for meaningful
averaging. It seems almost too simple. Aside from a low noise amp, what
am I missing? The board has a VGA port, 128 MB 5ns DDR2, and tons of I/O.
[/quote]
Just code :)
And a variable gain pre-amp/attenuator, if you want a useful Volts/Div
dynamic range.
-jg

John Fields · Guest

On Mon, 30 Jun 2008 18:41:49 -0700 (PDT), w_tom <w_tom1@usa.net>
wrote:

[quote]On Jun 30, 4:06 pm, John Fields <jfie...@austininstruments.com> wrote:
Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-basedsurgesuppressors can be used to good
advantage in premises without (or with unused) earth grounding.
That is, after all, the topic as indicated by the subject line.

Every responsible source says the grounding must exist.
[/quote]
---

<snipped off-topic, irrelevant claptrap>

Regardless of what your "responsible" sources say, situations exist
where grounding is impossible and the subject line of this thread:

"Surge protectors to use with home electronics when grounding is not
available?"

should indicate to anyone with a modicum of intelligence that it asks
for solutions for surge protection where no ground is available.

Your inane insistence on quoting references which require a ground is,
therefore, not only off topic but also stupid.

As I suggested earlier, if you want to discuss whole house protection
where earth grounding is available you would do well to start a new
thread addressing that topic.

Otherwise, perhaps you>d care to grace us with some on-topic solutions
or, at the very least, since you seem to be so intent on proving me
wrong, a technical refutation of my position with respect to the
subject at hand.

JF

Joel Koltner · Guest

"MikeWhy" <boat042-nospam@yahoo.com> wrote in message
news:q0lak.6030$LG4.5033@nlpi065.nbdc.sbc.com...
[quote]What>s involved in building a simple 50 MHz oscilloscope? I have a spare
Xilinx Spartan DSP board, and an unused LTC 105 MSps A/D chip in the part
box. The board>s 125 MHz clock is different enough from the sampling rate, I
think, to jitter the trigger point for meaningful averaging. It seems almost
too simple. Aside from a low noise amp, what am I missing? The board has a
VGA port, 128 MB 5ns DDR2, and tons of I/O.
[/quote]
That certainly builds a decent simple 'scope (and the amp doesn>t even have to
bet that low noise!). To compare with contemporary off-the-shelf offerings
you need...

-- A large amount of software to create a nice GUI, control the time base,
make measurements, do FFTs, display cursors, etc. Overall implementing the
software will probably take longer than implementing the hardware.
-- Decent triggering abilities. "Edge" and "level" are easy, but most scopes
today also do video triggering, serial protocol triggering, missed/runt pulse
event triggering, etc. Additionally, getting the display data to precisely
line up from one trigger to the next requires the ability to reset your
clocking system on a trigger event or some fancy software and a high-speed
timer to figure out when the "real" trigger event happened and shift the ADC>s
data (in time) accordingly. Without this, you>ll always have (upwards of) one
sample time worth of jitter on your signals -- many dirt cheap digital 'scopes
do suffer from this problem.
-- Some "smart" interface to the probes, if desired. Thees days all Tek and
Agilent scopes have a little serial protocol used to interrogate the "fancier"
probes so that the probe can tell them what scale and units to use (e.g.,
"This is a current probe, it produces 100mV/Amp.")
-- Connectivity to the outside world via USB, Ethernet, or (very old school)
RS-232 to save/print traces, data, etc.

---Joel

bud-- · Guest

w_tom wrote:
[quote]On Jun 30, 4:06 pm, John Fields <jfie...@austininstruments.com> wrote:
Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-basedsurgesuppressors can be used to good
advantage in premises without (or with unused) earth grounding.
That is, after all, the topic as indicated by the subject line.

No surge
protection stops or absorbs the common mode surge - surge that
typically causes appliance damage.
..[/quote]
Never explained - how does a common mode surge on incoming power lines
get past the N-G bond required in all US services.

And neither service panel or plug-in suppressors protect by "stopping"
or "absorbing".
..
[quote]As Bud>s NIST states:
..[/quote]
What does the NIST guide really say?
Plug-in suppressors are the "easiest solution".
..
[quote]Page 42 Figure 8 - a
protector too far from earth ground and too close to appliances
therefore leaves surge energy earthed 8000 volts destructivley through
an adjacent TV.
..[/quote]
The point of the illustration for the IEEE, and anyone who can think, is
"to protect TV2, a second multiport protector located at TV2 is
required." What a radical idea.
..
[quote]No way around what a protector does. Either it stops (absorbs)
surge energy OR is diverts (shunts, connects, clamps) that surge
energy into earth.
..[/quote]
The IEEE guide explains plug-in suppressors work primarily by CLAMPING
the voltage on all wires to the common ground at the suppressor. The
guide explains they do not work primarily by earthing. And they
certainly do not work by stopping or absorbing.
..
[quote]Who should the OP believe? John Fields? Or Sun Microsystems ...
and the IEEE, NIST
..[/quote]
The OP should believe the IEEE and NIST. Both say plug-in suppressors
are effective.
..
[quote]John do you really believe a hundred joules in a UPS or power strip
will stop (by absorbing) lightning energy?
..[/quote]
w_’s religious blinders prevent him from understanding how plug-in
suppressors work. It is not by stopping or absorbing.

And repeating:
"Because of arc-over and branch circuit impedance to surges,
surprisingly little surge current can reach a plug-in suppressor. That
means surprisingly little energy can reach a plug-in suppressor."

One-hundred Joules is a red herring. Plug-in suppressors with very high
ratings are readily available at low cost..
..
[quote]No problem.
Electronics routinely withstand 600 volt transients without damage - a
standard from 1970.
..[/quote]
Provide that standard.
..
[quote]Protection is about earthing.
..[/quote]
The IEEE guide explains that for plug-in suppressors, earthing occurs
elsewhere in the system, not primarily through the suppressor.

Still never seen - a link to another lunatic that agrees with w_ that
plug-in suppressors are NOT effective.

Why doesn’t anyone on a science newsgroup agree with you w_???

Still never answered - embarrassing questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in
suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- How would a service panel suppressor provide any protection in the
IEEE example, pdf page 42?
- Why does the IEEE guide say in the example "the only effective way of
protecting the equipment is to use a multiport protector"?
- Why does SquareD say "electronic equipment may need additional
protection by installing plug-in [suppressors] at the point of use."
– How can SquareD be a "responsible" company when there is no "spec that
lists each type of surge and protection from that surge".
- Where is the link to a 75,000A and 1475Joule rated MOV for $0.10.

- Was the UL standard revised as w_>s own hanford link said?
- Did that revision require thermal protection next to the MOVs as w_>s
own hanford link said?
- What was the date of that revision - which w_>s own hanford link said
was UL1449 *2ed*?
- Where specifically in any of w_>s links did anyone say a damaged
suppressor had a UL label?

Why no answers w_???

--
bud--

John Fields · Guest

On Tue, 01 Jul 2008 10:12:05 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

[quote]
John Fields wrote:

On Mon, 30 Jun 2008 18:41:49 -0700 (PDT), w_tom <w_tom1@usa.net
wrote:

On Jun 30, 4:06 pm, John Fields <jfie...@austininstruments.com> wrote:
Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-basedsurgesuppressors can be used to good
advantage in premises without (or with unused) earth grounding.
That is, after all, the topic as indicated by the subject line.

Every responsible source says the grounding must exist.

---

snipped off-topic, irrelevant claptrap

Regardless of what your "responsible" sources say, situations exist
where grounding is impossible and the subject line of this thread:

"Surge protectors to use with home electronics when grounding is not
available?"

should indicate to anyone with a modicum of intelligence that it asks
for solutions for surge protection where no ground is available.

Your inane insistence on quoting references which require a ground is,
therefore, not only off topic but also stupid.

As I suggested earlier, if you want to discuss whole house protection
where earth grounding is available you would do well to start a new
thread addressing that topic.

Otherwise, perhaps you>d care to grace us with some on-topic solutions
or, at the very least, since you seem to be so intent on proving me
wrong, a technical refutation of my position with respect to the
subject at hand.

JF

John, _wacko_ tom has been trolling this same crap for years. He
doesn>t want answers, he wants to argue.
[/quote]
---
That>s fine with me!

It>s a slow day and I don>t mind slapping the likes of him around at
all! :-)

JF

Michael A. Terrell · Guest

John Fields wrote:
[quote]
On Mon, 30 Jun 2008 18:41:49 -0700 (PDT), w_tom <w_tom1@usa.net
wrote:

On Jun 30, 4:06 pm, John Fields <jfie...@austininstruments.com> wrote:
Well, I see from your outburst that you>ve been confounded by my
excellent ASCII art schematics and my lucid explanation of why and how
two-wire plug-in TVS-basedsurgesuppressors can be used to good
advantage in premises without (or with unused) earth grounding.
That is, after all, the topic as indicated by the subject line.

Every responsible source says the grounding must exist.

---

snipped off-topic, irrelevant claptrap

Regardless of what your "responsible" sources say, situations exist
where grounding is impossible and the subject line of this thread:

"Surge protectors to use with home electronics when grounding is not
available?"

should indicate to anyone with a modicum of intelligence that it asks
for solutions for surge protection where no ground is available.

Your inane insistence on quoting references which require a ground is,
therefore, not only off topic but also stupid.

As I suggested earlier, if you want to discuss whole house protection
where earth grounding is available you would do well to start a new
thread addressing that topic.

Otherwise, perhaps you>d care to grace us with some on-topic solutions
or, at the very least, since you seem to be so intent on proving me
wrong, a technical refutation of my position with respect to the
subject at hand.

JF
[/quote]

John, _wacko_ tom has been trolling this same crap for years. He
doesn>t want answers, he wants to argue.

--
http://improve-usenet.org/index.html

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

Sporadic E is the Earth>s aluminum foil beanie for the 'global warming'
sheep.

w_tom · Guest

On Jul 1, 9:17 am, John Fields <jfie...@austininstruments.com> wrote:
[quote]Regardless of what your "responsible" sources say, situations exist
where grounding is impossible and the subject line of this thread:

"Surge protectors to use with home electronics when grounding is not
available?"
[/quote]
No equipment grounding is available at OP>s receptacles. That is
code acceptable. Not acceptable would be a missing earth ground at
breaker box. Breaker box ground must be installed to have any surge
protection (transistor safety) AND must exist to meet code
requirements for human safety. No way around that necessary earth
ground.

John, your ASCII diagrams were lucid. You did try to explain how
you thought surge protection works. But again, you did not even know
how MOVs perform and your calculation were for wire resistance. As a
result, what you thought was a potentially destructive surge - 8 amps
- is considered so trivial as to be made irrelevant by protection
already inside all appliances. Your calculations for 0.15 ohm
resistance (14 AWG wire) should have been using 130 ohms impedance for
that same wire.

Surge protecction is installed to earth 'tens of thousand' amp
surges without damage. Earth before surges can enter a building so
that protection inside all appliances is not overwhelmed. Routine is
a direct lightning strike to incoming utility wires without damage.
After all, telcos will suffer maybe 100 such surges during every
thunderstorm - without Central Office damage. To have no damage, all
telco COs use 'whole house' protectors and an even better earth
ground. What makes the protector even better? Better earthing.

Even Bell System papers in the 1950s (before transistors existed)
would discuss this surge threat. OP>s solution is the equivalent
solution found in transistorized COs today. Posted was a simplest
solution even for the OP and his 1950 vintage wiring - that also costs
less money.

No reason (for protection or for code requirements) to install
safety ground on any AC receptacles. Earthing electrode (required for
code requirements and surge protection) is essential for the
protection that the OP requests. No way around that necessary
earthing electrode and a short connection to one 'whole house'
protector.

Either the OP has only two wire receptacles and no protection (even
if using plug-in protectors). Or he has two wire receptacles, code
required earthing, one 'whole house' protector - and effective
protection. Those are his options.

As every responsible source notes, protection means:
[quote]... divert the power of the surge by providing a path
to ground for the surge energy. - Sun Microsystems
OR
... your surge protector will work by diverting the
surges to ground. - Bud>s NIST citation.
[/quote]
Protector is only as effective as its earth ground.


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