Toshiba TV29C90 problem; Image fades to black...

[Don Lancaster]

Floyd L. Davidson wrote:

Don Lancaster <don@tinaja.com> wrote:

DC, of course, cannot exist at all ever. Because it would have
to be unvarying through infinite time.


Boy, you are *pedantic*!

Can't we just define DC as current that doesn't vary "much"
for at last a "long" time. Granted that is ambiguous, but
what else would we the argue about, weather?

No.

Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value is
continuous.

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

"AC" or "DC" are gross and meaningless oversimplifications.

--
Many thanks,

Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Floyd L. Davidson]

Don Lancaster <don@tinaja.com> wrote:

Floyd L. Davidson wrote:
Don Lancaster <don@tinaja.com> wrote:

DC, of course, cannot exist at all ever. Because it would have
to be unvarying through infinite time.
Boy, you are *pedantic*!
Can't we just define DC as current that doesn't vary "much"
for at last a "long" time. Granted that is ambiguous, but
what else would we the argue about, weather?


No.

Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have
a waveform whose polarity continuously changes but whose average
value is continuous.

Hey, you moved *my* goal post! I said nothing about average
values. If it wiggles, it's AC. The difference is that
you are being so precise that you're saying if it wiggled since
the dawn of time, it's AC. I'm just saying that if it was so
long ago that I can't remember (which seems to be a pretty short
time anymore), that's long enough.

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

"AC" or "DC" are gross and meaningless oversimplifications.

EXACTLY! And while you and I can make jokes about just how
pedantic we should be with definition of terms, the fact is that
anyone who actually thinks "AC" and "DC" are the determinative
definitions based on word meanings, is going to be wrong.

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Floyd L. Davidson]

John Fields <jfields@austininstruments.com> wrote:

On Sun, 12 Jun 2005 14:00:23 -0800, floyd@barrow.com (Floyd L.
Davidson) wrote:

My point still stands, that if the current is changing, it is by
definition AC, and current not changing is DC. Trying to look
at it as DC is all in one direction and anything else is AC,
doesn't work.

---
Your point is flawed. Alternating Current, by definition, causes
electrons to move in one direction for a time, and then to reverse
direction for a time.

That isn't true.

The sinusoidally varying unipolar voltage under consideration _always_
forces electrons to move in one direction only.

A non-sequitor.

Since the voltage varies, the current will also, but the _direction_
in which the electrons are travelling will never change.

If it varies, it's AC.

That means that the signal is DC. A varying DC, but DC nonetheless.

If there is such a think as "varying DC", connect a load to
it... through a capacitor. Now, how do you describe the effect
that load has on your "varying DC". The load see's *only* AC,
even according to your definition. That AC came from somewhere,
and it certainly was not generated by the capacitor.

That's because AC is *not* defined by any change in direction,
but only by a rate of movement change.

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[John Fields]

On Sun, 12 Jun 2005 17:15:06 -0700, Don Lancaster <don@tinaja.com>
wrote:

Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value is
continuous.

---
No, you have a waveform with a polarity which changes _periodically_,
making it an AC signal. Do the electrons traversing the circuit
change direction? Yes. Do the electrons in a DC circuit ever change
direction? No.

Ergo, because of the periodic polarity reversals what you're looking
at is AC.
---

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

---
Why go there? Your description was adequate to indicate that polarity
reversals occur, therefore making the signal voltage alternate between
two different polarities, therefore making the current alternate
between polarities as well. That's why it's called "Alternating
Current".
---

"AC" or "DC" are gross and meaningless oversimplifications.

---
Uh-huh...

--
John Fields
Professional Circuit Designer

 

[CJT]

John Fields wrote:

On Sun, 12 Jun 2005 17:15:06 -0700, Don Lancaster <don@tinaja.com
wrote:


Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value is
continuous.

---
No, you have a waveform with a polarity which changes _periodically_,
making it an AC signal. Do the electrons traversing the circuit
change direction? Yes. Do the electrons in a DC circuit ever change
direction? No.

Ergo, because of the periodic polarity reversals what you're looking
at is AC.
---

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

---
Why go there? Your description was adequate to indicate that polarity
reversals occur, therefore making the signal voltage alternate between
two different polarities, therefore making the current alternate
between polarities as well. That's why it's called "Alternating
Current".
---

"AC" or "DC" are gross and meaningless oversimplifications.

---
Uh-huh...

It's not unusual to speak of the AC and DC _components_ of a

waveform that does not readily satisfy the simplification.

One also speaks of _DC offset_ of an otherwise AC signal.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.

 

[The Phantom]

On Sun, 12 Jun 2005 17:15:06 -0700, Don Lancaster <don@tinaja.com>
wrote:

Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value is
continuous.

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

"AC" or "DC" are gross and meaningless oversimplifications.

Didn't you just say in your immediately previous post:
----------------------------------------------------------------
""DC" is simply the first (or "offset" term in the Fourier expression
of
any repetitive waveform.

"AC" are all of the remaining components."
----------------------------------------------------------------
Did you intend to offer these descriptions knowing that they were
"gross and meaningless oversimplifications"? Why bother in that case?

 

[Do Little2]

"Arfa Daily" <monitech@ntlworld.com> wrote in message
news:R84re.7708$q46.1371@newsfe1-win.ntli.net...

We can also run high watts appliances such as ovens and driers, without
having to use cables as thick as your arm, and 6 inch nails for fuses. Oh,
and we also did away with ugly overheads and pole mounted transformers at
street distribution level, years ago ....

So your system is an upgrade ?? Hmmmm ...

True, serving about 330 million people,
compared to a few on a little island is
a real big upgrade...

Dolittle2

 

[Jamie]

Steve wrote:

My HK AVR-75's left front channel has almost no sound, and the sound it
does have is all high frequencies; no bass or midrange. The problem
occurs with any input, digital or analog, and with the speaker or
preamp outputs (so I'm pretty sure it's not in the power output
section). Any ideas? Please post here, or email to steve_wechsler (at)
yahoo(.)com (not the email I posted from; the spammers have taken it
over).

Thanks,

Steve

blown woofer?

or if its a multiple channel unit maybe you have a Class D amp
for the base and mid sections that is out

 

[operator jay]

"Kitchen Man" <nannerbac@yahoo.com> wrote in message
newsc5pa1d5hrfo4s0u7p3266ivcba95mff8o@4ax.com...

On Sun, 12 Jun 2005 12:21:01 -0500, "operator jay" <none@none.none
wrote:


Put an ammeter there and it says zero. That's zero. Electrons bouncing
around in the conductor have an average net displacement, over time, of
0.

"Put and ammeter there" and if it says +300mA to +800mA back and
forth, then it's Alternating Current, innit?

It is not changing polarity. I would hesitate to call it alternating
current. On the "dc sine wave" issue, I wouldn't even get into that debate.
To me the terms involved are open to too many interpretations. As evidenced
in this thread, I suppose.

j

 

[Floyd L. Davidson]

"operator jay" <none@none.none> wrote:

It is not changing polarity. I would hesitate to call it alternating
current. On the "dc sine wave" issue, I wouldn't even get into that debate.
To me the terms involved are open to too many interpretations. As evidenced
in this thread, I suppose.

Where *do* you get this requirement for changing polarity? We
don't call it "Alternating Polarity", we call it "Alternating
Current". If the current is being altered, it's AC. You keep
talking about AP, and it isn't the same.

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Jim Adney]

On 11 Jun 2005 16:12:06 -0700 "ed" <endeitz@gmail.com> wrote:

1. I have a cordless drill with an 18V nicad pack. At some point, the
charger failed (no voltage measured off the leads). I took the charger
transformer apart, found a tripped thermal fuse (only because it was
outside the coils) and replaced it. The charger worked again. I
started to charge the battery pack, but found that the tranformer was
getting very hot again. I measured the voltage in the battery pack
after 10 minutes of charging (the transformer was very hot by then) and
it was 12V. So I took apart the battery pack. Inside were 15 4/5 Sub
C nicad cells. 9 of the cells measured 1.2-1.3 volts on the voltmeter.
6 of the cells measured 0 volts. Hence the ~12V I guess.

You have 6 shorted cells, which means that the voltage opposing the
flow of current out of the charger is about 8V lower than the charger
expects. This leads to higher current draw from the charger. A more
elegant charger might cope with this, but clearly this one can't. I
suspect that if you just replace the bad cells, however, everything
will be fine again, until more cells die.

I would buy 6, or 15, new nicad, or 15 NiMH, replacement cells and fix
this pack.

Will using this 24V charger on the 19.2V pack damage the charger or the
battery pack? I understand that this is a really cheap drill, but how
can they in good conscience provide a mismatched charger/pack? Is it
because 24V transformers are so cheap?

It's hard to be sure about this, It might or might not work, but it
certainly won't work if the bad cells are still in there.

I'd still just replace the bad cells and then you have 2 good drills.
There are lots of places who can sell you the cells you need. Get the
cells you need with solder tabs attached and you can do this yourself.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Bob Penoyer]

On Sun, 12 Jun 2005 15:22:00 -0700, Don Lancaster <don@tinaja.com>
wrote:

Bob Penoyer wrote:


A rectified AC waveform contains DC and AC components but if the
current isn't changing direction, it isn't alternating current. And,
if it isn't AC, it's DC.


Total and utter horseshit.

Look, if the current's not alternating its direction, it's not
alternating current. To be clear, just because its amplitude is
changing does not mean it is alternating. In particular, a rectified
AC waveform it isn't changing direction.

There are certainly AC components in the waveform. But the sum of all
the components, including the DC component, never changes direction,
so the total signal is a DC signal. Here, "DC" does NOT mean
"constant"; it means unidirectional.

 

[ehsjr]

John Fields wrote:

On Sun, 12 Jun 2005 17:15:06 -0700, Don Lancaster <don@tinaja.com
wrote:



Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value is
continuous.


---
No, you have a waveform with a polarity which changes _periodically_,
making it an AC signal. Do the electrons traversing the circuit
change direction? Yes. Do the electrons in a DC circuit ever change
direction? No.

So you are saying that DC varying from 5 to 15 as the
op referenced is AC? If you put a DC source across
a capacitor and vary the source up and down, sometimes
electrons are flowing into the capacitor, and sometimes
they are flowing out of it. Same with an inductor.

For the record, I don't want to take one side or another
in the debate about AC vs DC in this thread. The waters
are muddy enough already. I view the op's scenario as
DC with an AC signal imposed on it.

This whole discussion of whether it is AC or DC is
a trap and diversion from the original. It does not
matter whether it is AC or DC that the components
see. For example, a capacitor operates the same on DC
as it does on AC. If there is a path for it to charge,
and a source sufficient to charge it, it charges. If
there is a path for it to discharge, and no source applied
sufficient to keep it charged, it discharges. Same thing
for an inductor below saturation.

The op asked about a sinusoidal varying DC, but gave
no info about frequency. He then asks about impedance
of the (unknown) RLC circuit. The answer has to be
arrived at by a consideration of how each component
reacts. To say (not that you said it) the cap won't pass DC
is crap. Connect a 15 V, 500 ohm relay coil to ground,
and the other side to a 470 uF cap. Connect the other
side of the cap to +12. The relay energizes briefly, proving
that the cap did pass DC. Try the same thing with a
supply that starts at 5 volts and increases to 15 volts
at a rate of 1 cycle per hour, and it does not energize.
But the relay coil DOES charge. For the op to understand
the load impedance, he has to understand what each component
does in his circuit. I see no other way to answer his
question, in the absence of specifics.

Ed

Ergo, because of the periodic polarity reversals what you're looking
at is AC.
---


Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.


---
Why go there? Your description was adequate to indicate that polarity
reversals occur, therefore making the signal voltage alternate between
two different polarities, therefore making the current alternate
between polarities as well. That's why it's called "Alternating
Current".
---


"AC" or "DC" are gross and meaningless oversimplifications.


---
Uh-huh...

 

[operator jay]

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87r7f7vvlr.fld@barrow.com...

"operator jay" <none@none.none> wrote:

It is not changing polarity. I would hesitate to call it alternating
current. On the "dc sine wave" issue, I wouldn't even get into that
debate.
To me the terms involved are open to too many interpretations. As
evidenced
in this thread, I suppose.

Where *do* you get this requirement for changing polarity? We
don't call it "Alternating Polarity", we call it "Alternating
Current". If the current is being altered, it's AC. You keep
talking about AP, and it isn't the same.

You are the one with the requirements, assertions, and definitions, not me.
Where are you coming up with them? If it's from the same place where
- zero current is not definable
- magnitude of current needs an outside reference
- voltage and current are for all practical purposes different expressions
of the same thing
- alter is the same thing as alternate
then I don't even want to know.

You need to come to realize there is no clear cut correct answer on this
'AC' vs 'DC' issue at this time. If there was one, there would be much more
consensus between people on what the correct answer is. This big long
thread would not have occurred. Now let's turn it around and look at it the
other way. This big long thread did occur. We can plainly see that there
is disagreement between groups on what exactly the precise meanings of AC
and DC entail. Therefore there effectively is no single exact definition
for "AC" or for "DC" that will allow us to resolve which is correct and
which is not correct.

Picture my flashlight, battery powered. Generally this is considered a dc
circuit. When I turn it on or off, there is 'change'. So is it in fact an
AC flashlight? If the battery starts to die there is a change so is it in
fact an AC battery? Etcetera. (These questions are rhetorical by the way).
I know better than to try to pin a strict name on these things where there
is not an (adequately) universal and strict definition.

On another note, how long are the days getting to be way up there? Do you
get continuous sunshine?

j

 

[ehsjr]

Kitchen Man wrote:

On Sun, 12 Jun 2005 14:33:39 -0500, John Fields
jfields@austininstruments.com> wrote:


On 12 Jun 2005 09:01:11 -0700, mabelmapleleaf@yahoo.com wrote:


It's a shame you have to weed thru all the crap from some
of the posters here who have a lot of time on their hands and
have no tolerance for those who are just learning their craft....

---
It's a shame that those of us who give of our time in an effort to
edify the ignorant are often abused by imbeciles who can't take
correction gracefully.


It is equally a shame that there are those that are sometimes
incapable of offering correction gracefully, eh, John? If it pains
you so much to engage in your ungracious edifying, perhaps you would
do well to bugger off, and leave the stress of educating imbeciles to
those with more patience.

Interesting! I thought John's response to the op was
called for. The OP is going to get himself into trouble
with the attitutde he's exhibited. In my opinion, John
saw through the BS and called a spade a spade. I don't
know whether the OP got it or not - but John made it
clear that the BS wasn't fooling anybody.

I'll have to go back and read it again in light of
your post.

Ed

 

[Michael Kennedy]

Well I didn't mean all of the newsgroups. I meant to say a lot of the
newsgroups. I know Earthlink doesn't host all of the newsgroups either, I
have comcast now and they have many newsgroups not avaible on earthlink.


"Alan Smith" <alan@hidden.email> wrote in message
news:d8h6k1$938$1@news8.svr.pol.co.uk...

google doesn't have all newsgroups, I just looked for archives of one
yesterday and they don't hold them.



"Michael Kennedy" <Mikek400@nearthlink.net> wrote in message
news:B-mdnWdUOo2lRDbfRVn-3Q@comcast.com...
Can google shut someone down?? I thought google just runs an archive of
all the newsgroups. I don't use google I use my ISP's Newsgroup server
through outlook. I wonder who actually runs the newsgroup servers.


"NSM" <nowrite@to.me> wrote in message
news:Y2Fqe.44931$on1.29162@clgrps13...

"CRaSH" <sorry@aint-here.spam.com> wrote in message
news:UaEqe.6951$7s.1754@fed1read01...

shred wrote:
if theres one thing i can't stand it's born again christians....if
theres someting else i can't stand it's born again christians in the
wrong place,,...keep it for church

Judging from the groups listed, the OP jacks off while working on his
WIN-98
computer, in his Mustang........
Man, what a hand full (computer wise that is.. ..................

He's a notorious spammer who Google refuses to shut down.

N

 

[Michael Kennedy]

Loony? I don't think so. We will know the answer to this question one day.

"Bob Parker" <bobpdeletethis@despammed.com> wrote in message
news:tcuoa1hp096bhs8istus9s23lg5ss8t4qq@4ax.com...

It's because of this kind of irrelevant garbage that I've haven't
taken newsgroups seriously for a long time and barely glance at them
now. It's true: "On the internet, things which usually live under
rocks are suddenly in your face".
I'm sure there's a newsgroup for "born-again loony Christians".
Please go there and stop wasting our time and bandwidth.



"Helen" <@abuse.roman.gov> wrote:


"Katt" <seruhshjaudn@dfhu.net> wrote in message
news:dmYqe.7425$q46.942@newsfe1-win.ntli.net...
"Helen" <@abuse.roman.gov> wrote in message
news:kVWqe.686$zm.363@bignews4.bellsouth.net...

The pathetic ego of this Troll suffices as evidence
that this is atheistic behavior
designed to elicit the exact response you gave.

Curious comment. Ego = atheist?

Katt.


It was his(?) benefit and he'll know exactly what it means.
"Beware a little leaven in the bread...."
And....
"They willl say, 'didn't I do thus and such for you?" And
didn't I, and didn't I, and didn't I....I I I I-I- I....
And HE will say, 'get away from me, I never knew you!"

By their fruits shall ye know them.

 

[Kitchen Man]

On Sun, 12 Jun 2005 16:50:51 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 12 Jun 2005 13:39:22 -0700, Kitchen Man <nannerbac@yahoo.com
wrote:

On 10 Jun 2005 23:06:10 -0700, jackbruce9999@yahoo.com wrote:

You actually proved my
point that DC is DEFINED (i.e. by convention) as "zero frequency".
Is it that weird to posit that the superior concept with respect to
considering any signal as AC or DC, be the actual NET current flow? I
could see your point if signals were classified as either "ZF" ("zero
frequency") or "NZF" (non-zero frequency") but we are dealing with "DC"
or "AC"

If nothing else, your stubborn adherence to a flawed terminology and
lack of openness to furthering your understanding will make you look
like an idiot in a job interview, should you ever decide to pursue
career advancement in the electronics industry. Please note that I am
not saying you are an idiot, just that you will look like one in an
interview. The interviewers will assume you know very little about
the basics of the craft if you carry on like this, or at the very
least will see you as a detriment to teamwork. HTH.

---
His attitude, if he persists with it, will be a serious detriment no
matter what field of endeavor he chooses to enter.

Oh, I agree. I just think it helps to be a bit patient. Not that I'm
all that good at patience, myself. But we should try. We have all
been rookies, once or twice.

Starting to see it my way, Al?-)

--
Al Brennan

"If you only knew the magnificence of the 3, 6 and 9,
then you would have a key to the universe." Nicola Tesla

 

[Kevin Aylward]

Don Lancaster wrote:

Floyd L. Davidson wrote:
Don Lancaster <don@tinaja.com> wrote:

DC, of course, cannot exist at all ever. Because it would have
to be unvarying through infinite time.


Boy, you are *pedantic*!

Can't we just define DC as current that doesn't vary "much"
for at last a "long" time. Granted that is ambiguous, but
what else would we the argue about, weather?


No.

Sum a 1 volt peak sinewave with a 0.6 volt dc term and you have a
waveform whose polarity continuously changes but whose average value
is continuous.

Looking at the Fourier terms makes this waveform perfectly clear.
Calling it "AC" or "DC" does not.

"AC" or "DC" are gross and meaningless oversimplifications.

That's going a bit far. "Meaningless" means no meaning, and that is not
really an accurate description for the terms AC and DC. They have a
pretty well understood meaning, despite some suggestions in this thread.

"quotes with no meaning, are meaningless" - Kevin Aylward


Kevin Aylward
informationEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[Kevin Aylward]

Floyd L. Davidson wrote:

Bob Penoyer <bob@NOSPAMbobpenoyer.com> wrote:
On Sat, 11 Jun 2005 10:36:54 -0400, "Tam/WB2TT"
t-tammaru@c0mca$t.net> wrote:

snip

Yes. DC by definition is zero frequency.

Um, no. DC is Direct Current, i.e., current that flows in one
direction. For example, the output from a rectifier is DC but it
certainly isn't "zero frequency."

Actually, DC from a rectifier *is* "zero frequency", to the
degree that it is DC. Of course until the AC is filtered out,
it has both AC and DC components.

The output of a rectifier contains both AC and DC. You put a filter
on it to get close to pure DC.

That is *precisely* correct. (It just doesn't tell enough of
the story to explain the confusion of this "flows in one
direction" definition of DC.)

A rectified AC waveform contains DC and AC components but if the
current isn't changing direction, it isn't alternating current. And,
if it isn't AC, it's DC.

The output of a rectifier until filtered *does* have both AC and
DC, which actually is another way of saying that yes it *does*
change directions.

What? you say!

The problem is that "direction" only has meaning when measured
in comparison some specific point of reference. If you have
three different reference points, one at the DC level, one at
the peak positive swing and one at the peak negative swing, you
have three very different views of "direction" for current flow:

Since we are quibbling her on terms, lets get this bit straight shall
we.

"Current flow" is wrong. Its simply "current" or "charge flow".
"Current" already contains the notion of "flow".


Kevin Aylward
informationEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.