Chip with simple program for Toy

[Phil Allison]

"The Phantom"
"Phil Allison"

For example, for the 24 volt, 8 amp transformer I've mentioned in this
thread,

** An incorrectly rated example.

Plucked out of his arse.


The recommendation that John Fields made, to assume Irms/Idc = 2,
which he says will always be safe, may not be safe if you are using a
transformer with good regulation and if your grid waveform is a good
sinusoid.


** A transformer with unusually good regulation ALSO has unusually LOW
temp
rise.

A transformer with unusually good regulation was presumably rated that way
by
the manufacturer for some reason.

( snip even worse DRIVEL )


** How completely ASININE !!

A transformer with unusually good regulation = a transformer that is
being under utilised !!!

No need for exists for transformer makers to make special high regulation
models - the customer simply picks a model with more VA capacity than
strictly needed !!!

Piss off - you PITA fool.



....... Phil

 

[Phil Allison]

"The Phantom Congenital LIAR "

** The 8% figure is for the lowest temp grade insulation in common use.

But there are still lower temperature grades available.

** No.

We're talking about *this* transformer,

** No *we* are not - asshole.

Using an isolated example to prove a case is false logic.

Using an isolated example that only you know about is a classic debating
cheat.

Combining the two, as you have done, is the act of a desperate LIAR.

You have no case to put - fuck off.



....... Phil

 

[Phil Allison]

"John Fields"

** How completely ASININE !!

A transformer with unusually good regulation = a transformer that is
being under utilised !!!


Explain that a transformer that might be seen as being under-utilized
while feeding a resistive load might have to be as big as it is in
order to drive reactive loads which pump current back and forth
instead of just forth.

** What is the heading on this thread ???

So what is the context ?

No need for exists for transformer makers to make special high regulation
models - the customer simply picks a model with more VA capacity than
strictly needed !!!


Generally true, but there _are_ those exquisite ferroresonant
transformers

** What is the heading on this thread ???

So what is the context ?

Is being a context shifter related to being a shirt lifter ?



....... Phil

 

[Phil Allison]

"The Phantom"



Piss off - you PITA BLOODY TROLL.




...... Phil

 

[Paul E. Schoen]

"The Phantom" <phantom@aol.com> wrote in message
news:urmv74l94pn1n49mjsijnevvjdb5tlohtp@4ax.com...

If we assume Irms/Idc <= 2, and if it isn't, because the transformer has
low
internal resistance, then the secondary current will be higher than we
expected.
This may or may not cause a problem, but there is probably some reason
the
secondary current had a rated value. Perhaps the transformer was
originally
used in an enclosure without adequate ventilation, and cannot be allowed
to get
as hot as it might otherwise. Whatever the reason for the given
secondary
current rating, exceeding it is at the user's risk, and the user ought to
know
about it. If the transformer/rectifier combination will be used in a
better
environment than the transformer without rectifier was originally
designed for,
then there may be no problem. But if Irms/Idc could be > 2 in some
circumstances, the user should know what those circumstances might be.

Interestingly, with respect to your reply to whit3rd and the behavior he
described, the analysis I came up with seems to have a limit to the ratio
Irms/Idc. I allowed the transformer internal resistance to become orders
of
magnitude lower than would ever be possible in the real world, without
superconducting wire, and the calculated Irms/Idc never got over 4, no
matter
how peaky the waveform. I wonder what simulation would show. It might
be
numerically difficult for a simulator to correctly calculate the RMS
value of a
spike of current whose duration is one billionth of the period!

What will limit the narrow high current spikes you are talking about will

ultimately be the inductance of the other circuit components and their
internal resistance, and the diode characteristics. Also, the current
spikes are a function of the rate of rise of the waveform at the time of
onset of conduction (which also is not immediate), and the size of the
capacitor. For low values of capacitance, the conduction occurs on a faster
rising portion of the waveform, but the peak current is limited because the
capacitance is smaller. As you increase the capacitance, the spikes are
greater, and RMS current can be high enough while charging the capacitor to
exceed the transformer's specifications and overheat or even
instantaneously blow the windings, but that would be an extreme case.

For real life, reasonable circuits, after a large capacitor has charged to
its final value, the diodes will conduct only when the waveform is greater
than the diode forward drop and the minimum output voltage excursion (Max
DC - P-P ripple), and this will occur very close to the nearly flat top of
the sine wave, so the slew rate is very slow. Eventually the lower slew
rate is balanced by the high capacitance so the peak current will be
limited, and the Irms/Idc reaches a maximum value, such as the figure of 4
you mentioned.

Ordinary waveform distortion (and normal transformer saturation) will
usually cause a flattening of the peaks and an even slower slew rate. If
the waveform somehow has sharp peaks, like a triangle wave, this indicates
high frequency harmonics, and peak currents can become extreme. But that is
a very rare situation, and it may cause transformer overheating even with
an AC load, due to excessive saturation. We must assume reasonable power
quality.

Paul

 

[Phil Allison]

"Paul E. Schoen"

Ordinary waveform distortion (and normal transformer saturation) will
usually cause a flattening of the peaks

** Where in time are the current peaks from Imag ( or Isat) ???

Engage brain, before putting mouth in gear.



..... Phil

 

[Paul E. Schoen]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6eaq93F69ejvU1@mid.individual.net...

"Paul E. Schoen"


Ordinary waveform distortion (and normal transformer saturation) will
usually cause a flattening of the peaks


** Where in time are the current peaks from Imag ( or Isat) ???

Engage brain, before putting mouth in gear.

The transformer will have current peaks that coincide with the peaks of
applied sinusoidal voltage. The output of the transformer will have the
voltage peaks flattened where the current peaks occur.

Paul

 

[Phil Allison]

"Paul E. Schoen"
"Phil Allison"

Ordinary waveform distortion (and normal transformer saturation) will
usually cause a flattening of the peaks


** Where in time are the current peaks from Imag ( or Isat) ???

Engage brain, before putting mouth in gear.

The transformer will have current peaks that coincide with the peaks of
applied sinusoidal voltage.

** No way - there is a 90 degree phase lag ( ie inductive load ..... )
that means currents peaks are at or near the supply voltage zero crossings.

The output of the transformer will have the voltage peaks flattened where
the current peaks occur.

** See above.

Hard to believe that someone who spends so much time * wrangling * with
some very serious transformers was unaware.



..... Phil

 

[Phil Allison]

<stephen@stephenhobley.com>

I was given the parts to build this sine wave generator. As far as I
can tell it's a Wein Bridge with the two LEDs serving the function
originally reserved for the incandescent lamp.

** Yep.

http://www.stephenhobley.com/sinewave.gif

Unfortunately it's fixed frequency, the 5K variable only trims one
"side" of the wave, not selecting the fundamental as I'd hoped.

* It acts as a fine frequency trim only.

It
looks liket the 68K resistors and 0.047uF caps determine the period of
oscillation (one pair for each half).

** The cap is actually 0.0047 uF.

Makes the frequency just on 500Hz.

F = 1 / 2.pi.R.C

Does anyone know the mathmatical relationship between the values of R5/
R6 and C1/C2 and the frequency of oscillation? I'd like to get this
working in the 30Hz range.

** Change C1 & C2 to 0.082 uF ( 82nF)

Gives you about 29 Hz.



.... Phil

 

[Tom Biasi]

"sp" <swapnapriya2020@gmail.com> wrote in message
news:bfff5b62-83cf-40d7-8b8b-89dfb9a9fbb4@p31g2000prf.googlegroups.com...

Hai

I have a small doubt about PCB Layout

At turning point could we do route at 45 degree's , some one told in
PCB manufaturing the edge will cutout,we cannot see by eye's,we can
see that by microscope only.

suppose we do route at 90degree 's ,may be that path current will be
short

plse anybody tell

what is the correct one and reasons



Thank u

It is common practice not to turn a trace less than 90 degrees.
Tight turns make pockets in the wave soldering process.
Sharp edges may be a concern in super high frequency application also.
Tom

 

[Tom Biasi]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4880D007.CB6C78EA@hotmail.com...

Tom Biasi wrote:

It is common practice not to turn a trace less than 90 degrees.
Tight turns make pockets in the wave soldering process.
Sharp edges may be a concern in super high frequency application also.

Surely you mean more than 90 degrees ? Unlesss I completely misunderstood
the
question.

Graham

I believe he was referring to acute angles.

When I designed boards it was common practice not to turn at acute angles
for the reasons I mentioned.
But as John says, It really is not all that important.

Tom

 

[Neil]

"Randy Day" <randy.day@shaw.cax> wrote in message
news:487FBC8C.DC2BF812@shaw.cax...

sodaant@gmail.com wrote:
Are there any schematic capture/board layout applications available
for Windows that don't cost an arm and a leg, yet are reasonably
functional?
EasyPCB is the only one I'm familiar with, but I'd rather have
something that I can use to design and layout boards to be built by
other companies.
Kicad
http://www.lis.inpg.fr/realise_au_lis/kicad/
I've sent their Gerber files out to get PCB's made, with no
problems.
I haven't tried multi-layer stuff, though...
I've used EasyCad (from Fastcad.com) for schematic - it's meant for 2D

stuff, but since we had it at work, I tend to use it out of familiarity and
convenience. If you buy it it is around $300 I think for a license.
Then manually type the netlist in PADSPCB format. Sounds laborious, but not
too bad, and the extra time means I notice things that should be on the
circuit but aren't.
I tried KICAD but am so familiar with Easycad that the learning curve seemed
too steep. And it didn't make as pretty coloured drawings.

FREEPCB seems really handy for layouts, taking the netlist in along with
component shapes. Sometimes notice things missing again ! Edit to netlist
and re-import. I lashed up a little program to extract the parts and nets
into simple lists to make sure all the nets were imported correctly. Just
don't trust myself - with good reason.
Works up to 16 layers (iirc). Just waiting for first pcb to come back from
PCBCART in China to see if it all hangs together for a doublesided, then
will try their 4 and 6 layer.

hth
Neil

 

[Tom Biasi]

"DJ Delorie" <dj@delorie.com> wrote in message
news:xnfxq79bg7.fsf@delorie.com...

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> writes:
The high voltage boys don't like sharp features.

PCB uses round-end traces all the time, so even on 90 degree corners
the outside edge has a (width/2) radius bend in it. What do other EDA
packages do? Do any of them use sharp outside corners?
The radius is not necessary. It was used back in the tape and light table

days but for CAD progs its just style.

Tom

 

[Tom Biasi]

"DJ Delorie" <dj@delorie.com> wrote in message
news:xn7ibiaod2.fsf@delorie.com...

"Tom Biasi" <tombiasi***@optonline.net> writes:
The radius is not necessary. It was used back in the tape and light
table days but for CAD progs its just style.

Actually, in PCB we use round ends because otherwise we have to
compute gerber apertures separately for each trace angle and end
junction.

Maybe you're confusing "round end caps" with "the trace bends" ? I
mean the former when I say "round ended traces".

Sounds like a good enough reason for me.

Tom

 

[Bob Eld]

<stephen@stephenhobley.com> wrote in message
news:ff5ad5b2-0602-43a7-a7da-96c4693943f0@a3g2000prm.googlegroups.com...

I was given the parts to build this sine wave generator. As far as I
can tell it's a Wein Bridge with the two LEDs serving the function
originally reserved for the incandescent lamp.

http://www.stephenhobley.com/sinewave.gif

Unfortunately it's fixed frequency, the 5K variable only trims one
"side" of the wave, not selecting the fundamental as I'd hoped. It
looks liket the 68K resistors and 0.047uF caps determine the period of
oscillation (one pair for each half).

Does anyone know the mathmatical relationship between the values of R5/
R6 and C1/C2 and the frequency of oscillation? I'd like to get this
working in the 30Hz range.

Thanks,
Steve

The frequency of oscillation of a Wien Bridge is: f = 1/(2*pi*(R5*(R6 +
R9)*C1*C2)^1/2).

The R's and C's are the same sub numbers as your schematic. There is no
requirement that R5 = R6 or C1 = C2. That's just a convenience. When those
components are equal, the above formula simplifies as can be seen and was
posted. When the components are equal, the gain must equal exactly 3. The
purpose of the feedback network with the LED is to allow the gain to
automatically adjust to the right value for oscillation.

If the R and C values are not equal, a different gain than 3 will balance
the bridge for stable oscillation. The gain is critical, too much and the
output slams into the amplifier limits and too little and the oscillation
quickly dies out. The LED's help stabilize the gain by lowering the gain
when the drive gets too high at which point the LED's conduct more.

Because the LED's conduct at the top (and bottom) of the sine cycle, this
method of stabilization adds some distortion to the sine wave which may be
ok depending what you intend to do with the signal.

 

[Paul E. Schoen]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6eb1v3F67vuuU1@mid.individual.net...

"Paul E. Schoen"
"Phil Allison"

Ordinary waveform distortion (and normal transformer saturation) will
usually cause a flattening of the peaks


** Where in time are the current peaks from Imag ( or Isat) ???

Engage brain, before putting mouth in gear.

The transformer will have current peaks that coincide with the peaks of
applied sinusoidal voltage.


** No way - there is a 90 degree phase lag ( ie inductive load
..... ) that means currents peaks are at or near the supply voltage zero
crossings.


The output of the transformer will have the voltage peaks flattened where
the current peaks occur.

** See above.

Hard to believe that someone who spends so much time * wrangling * with
some very serious transformers was unaware.

OK, you are right on this point, and the flattened voltage waveforms and
peaked current waveforms I have seen may be due to the fact that the
circuit breaker loads may be highly inductive, or contain current
transformers with non-linear diode and capacitor loads that draw more
current at the peaks.

For breaker testing, I'm usually looking at the current, and I often see a
peaked waveform, while the voltage appears to be flattened. But it could be
a reflection of distortion on the input waveform. When drawing several
hundred amps from a 480 VAC line, to pump 30,000 amps or more into a
breaker, strange things can happen.

The following waveforms show flattening as I have seen, but maybe it was a
clipped waveform to begin with:
http://www.bookcracker.com/transformer/

This paper shows saturation occurring near the zero crossing, when the
volt-seconds of the primary is reached:
http://www.rane.com/pdf/ranenotes/Unwinding%20Distribution%20Transformers.pdf

and this also shows current peaks just before each zero crossing, and no
apparent flattening.
http://www.ibiblio.org/kuphaldt/electricCircuits/AC/AC_9.html

Here is some good information (but mostly a copy of the above):
http://www.allaboutcircuits.com/vol_2/chpt_9/8.html

I seem to recall ferroresonant regulating transformers having flattened
waveforms.
http://www.alpha.com/files/documents/016538B0002_revB.pdf

I found this interesting:
http://www.ece.mtu.edu/faculty/bamork/FR_WG/Panel/WallingFerroPanel.pdf

Paul

 

[Phil Allison]

<stephen@stephenhobley.com>

That's great thanks - I ordered some caps close to your value, and a
ganged 200K dual pot - I should be able to get pretty close now.

** You will have a large range of frequencies available now.

From about 10 Hz up to 200 Hz or more.



...... Phil

 

[Paul E. Schoen]

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news3u6841m0gkfu88flpdgtsmdm3jfj6945e@4ax.com...

On Sun, 20 Jul 2008 10:08:42 -0700 (PDT), Bret Cahill
BretCahill@aol.com> wrote:

Supposedly if the tank is connected to the vehicle's engine, it's
technically legal to bring 8 pesos/litre [$3/gallon] fuel across the
border from Mexico. If the tank isn't connected, customs wil seize
the diesel and maybe even the vehicle. Even if it is connected,
customs may give you a hard time. Supposedly a driver can earn $100 a
trip running diesel in border areas but each border crossing takes an
hour or so . . .

It's a whole lot more cost effective to just electrify the #@!%&*!
tractors and fields.

A 1/2 mile long wire 10 - 20 feet above the ground only needs to be
on one end of a quarter square. A fast discharge battery can be
relatively small as the tractor only needs to go one mile for the
round trip back to the wire. An on board ICE or battery trailer could
be used to relocate the tractor any distance.

As agriculture become more automated there won't be any reason for
anyone to be in the tractor so no one will get bored as the tractor
lingers for a minute or so charging up at the wire.

What sort of battery charges in a minute or two? And where would all
that power come from, in the middle of a corn field?

Do the math: say, 50 horsepower-hours:

How much power to recharge in two minutes?

What would the voltage have to be to keep the
wire losses reasonable?

How much do the batteries weigh?

How much do the batteries cost?

Ideas are cheap, as long as you ignore reality.

I think this could also be accomplished by stringing a grid of wires over
the field, and using a trolley that rides on the wires. It's not as simple
as a locomotive or streetcar, where a single hot wire can bu used, and the
return current through the tracks. But I think a system could be devised to
provide electricity to a tractor by means of a controlled tether. It could
definitely be done with a set of tracks that would move the supply line to
be in-line with the movement of the tractor, and then have a trolley with a
power cord that supplies the tractor. It would involve some engineering,
initial investment, and maintenance, but should be about 95% efficient for
energy conversion.

Paul

 

[Doug Miller]

In article <RPOdnWl2eNeB7B7VnZ2dnUVZ_gGdnZ2d@earthlink.com>, "Michael A. Terrell" <mike.terrell@earthlink.net> wrote:

"David M Lemcoe Jr." wrote:

Is there ANY attempts being made to cut down on the spam in the channel?
I mean I think it is rediculous that the same few spammers spam on this and
other newsgroups I belong to (namely comp.lang.python). If a moderator is
needed I would more that gladly become a moderator.


First of all, news:sci.electronics.basics was not created as a
moderated newsgroup, and that can not be changed without creating a new
newsgroup.


If you want to do something about spam, install NewsProxy and drop
all traffic from Google groups. You can whitelist the few regulars who
use 'Google Groups'.

What he said.

You can drop AIOE.org as well. Newsproxy is available at the link in my
sig file. This has been discussed to death on
news:sci.electronics.design where people can give you a copy of their
filter if you request it.

And likewise on rec.woodworking -- which has been occasionally subjected to

fierce troll attacks over the years, leading many of the regulars to become
*quite* proficient at creating filters.

See my sig, too...


--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)

Join the UseNet Improvement Project: killfile Google Groups.
http://www.improve-usenet.org

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter
by sending email to autoresponder at filterinfo-at-milmac-dot-com
You must use your REAL email address to get a response.

Download Nfilter at http://www.milmac.com/np-120.exe

 

[Doug Miller]

In article <d2bba4f224b08cab87bf5e22de7@newsgroups.bellsouth.net>, David M Lemcoe Jr. <lemcoe9@bellsouth.net> wrote:

Is there ANY attempts being made to cut down on the spam in the channel?

What spam? I haven't seen any. I mean, none. Zip. Zilch. Nada.

Oh! You must not be using any filters! *That* would explain it.

--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)

Join the UseNet Improvement Project: killfile Google Groups.
http://www.improve-usenet.org

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter
by sending email to autoresponder at filterinfo-at-milmac-dot-com
You must use your REAL email address to get a response.

Download Nfilter at http://www.milmac.com/np-120.exe