Guest
On Monday, 19 August 2019 13:08:53 UTC+1, Bill Sloman wrote:
Violet rays don't emit ultraviolet. Fool.
NT
Violet rays don't emit ultraviolet. Fool.
NT
W
whit3rd
Guest
On Sunday, August 18, 2019 at 9:53:53 AM UTC-7, Jan Panteltje wrote:
If you have a fluorescent fixture that won't start, hold the output end up to the tubes.
I've gotta replace the tubes and/or ballast eventiually, but the Zerostat (another kind of sparker)
is still starting my basement lights at need.
If you have a fluorescent fixture that won't start, hold the output end up to the tubes.
I've gotta replace the tubes and/or ballast eventiually, but the Zerostat (another kind of sparker)
is still starting my basement lights at need.
B
Bill Sloman
Guest
On Monday, August 19, 2019 at 9:08:26 PM UTC+10, tabb...@gmail.com wrote:
Ultraviolet rays are also good creating melanomas in your skin.
You should know enough to know the difference between UVA and UVB if you want to give useful advice, which is beyond NT's capabilities, if not perhaps beyond the capabilities he claims.
https://www.skincancer.org/risk-factors/uv-radiation/
--
Bill Sloman, Sydney
Ultraviolet rays are also good creating melanomas in your skin.
You should know enough to know the difference between UVA and UVB if you want to give useful advice, which is beyond NT's capabilities, if not perhaps beyond the capabilities he claims.
https://www.skincancer.org/risk-factors/uv-radiation/
--
Bill Sloman, Sydney
P
Piotr Wyderski
Guest
Tim Williams wrote:
> A few uJ at best.
The compact nanoperm-based ones saturate at even lower currents than
those wound on a ferrite core. This crazy permeability doesn't come for
free. And their hi-freq permeability sucks even more.
}:->
Best regarads, Piotr
> A few uJ at best.
The compact nanoperm-based ones saturate at even lower currents than
those wound on a ferrite core. This crazy permeability doesn't come for
free. And their hi-freq permeability sucks even more.
}:->
Best regarads, Piotr
P
Piotr Wyderski
Guest
jlarkin@highlandsniptechnology.com wrote:
For this application air-core coils would be best. They melt, but not
saturate. You can minimise their count by tapping. 250uH made of 1mm
wire is not very big, 4cm OD or so. I wound several of them for surge
suppression. The small inductance ones can even be air-core toroids.
Best regards, Piotr
For this application air-core coils would be best. They melt, but not
saturate. You can minimise their count by tapping. 250uH made of 1mm
wire is not very big, 4cm OD or so. I wound several of them for surge
suppression. The small inductance ones can even be air-core toroids.
Best regards, Piotr
Guest
On Mon, 19 Aug 2019 14:54:22 +0200, Piotr Wyderski
<peter.pan@neverland.mil> wrote:
OK, I'll try some math on air-cores.
Looks like drum cores might work:
https://www.digikey.com/product-detail/en/bourns-inc/1140-102K-RC/1140-102K-RC-ND/2534469
Lots of air gap, lots of cooling area, Isat>Irms. It will spray
h-field in all directions, but that would be OK in my application.
It's BIG.
I'm thinking about a single 1 mH coil, then synthesizing the rest of
the inductance.
A couple of off-the-shelf toroids in series would hit 1 mH with that
sort of saturation. Then I could offer 500uH or 1 mH as the switched
"real" inductances.
Lots of inductors are like ceramic caps, only providing the specified
reactance at a fraction of the rated voltage or current.
<peter.pan@neverland.mil> wrote:
OK, I'll try some math on air-cores.
Looks like drum cores might work:
https://www.digikey.com/product-detail/en/bourns-inc/1140-102K-RC/1140-102K-RC-ND/2534469
Lots of air gap, lots of cooling area, Isat>Irms. It will spray
h-field in all directions, but that would be OK in my application.
It's BIG.
I'm thinking about a single 1 mH coil, then synthesizing the rest of
the inductance.
A couple of off-the-shelf toroids in series would hit 1 mH with that
sort of saturation. Then I could offer 500uH or 1 mH as the switched
"real" inductances.
Lots of inductors are like ceramic caps, only providing the specified
reactance at a fraction of the rated voltage or current.
B
Bill Sloman
Guest
On Monday, August 19, 2019 at 10:32:32 PM UTC+10, tabb...@gmail.com wrote:
Obviously not. The violet end of the spectrum extends into the ultraviolet.
The violet band that you can see isn't exactly active, so the foolishness is all yours - as usual. More transparently so than usual.
--
Bill Sloman, Sydney
Obviously not. The violet end of the spectrum extends into the ultraviolet.
The violet band that you can see isn't exactly active, so the foolishness is all yours - as usual. More transparently so than usual.
--
Bill Sloman, Sydney
T
Tim Williams
Guest
"Piotr Wyderski" <peter.pan@neverland.mil> wrote in message
news:qje6d2$1avh$2@gioia.aioe.org...
Although they make some that they claim higher saturation current (like up
to 40mAt) for; or rather, a softer B-H curve.
There's also square B-H varieties for magamp use.
The HF permeability sucks in that it begins dropping at quite low
frequencies: a half-corner ~10kHz, then a full corner ~1MHz.
https://www.seventransistorlabs.com/Images/CurveFit1.png
https://www.seventransistorlabs.com/Images/CurveFit2.png
The half-corner corresponds to the skin depth of the material (hence the
characteristic sqrt(f) diffusion slope), and the full corner corresponds to
the capacitance between laminations, so, the width and spacing of them.
It's overall better than any ferrite, particularly at low frequencies. And
if you have a lot of noise to handle, Bmax is also much higher. Awesome
stuff.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
news:qje6d2$1avh$2@gioia.aioe.org...
Although they make some that they claim higher saturation current (like up
to 40mAt) for; or rather, a softer B-H curve.
There's also square B-H varieties for magamp use.
The HF permeability sucks in that it begins dropping at quite low
frequencies: a half-corner ~10kHz, then a full corner ~1MHz.
https://www.seventransistorlabs.com/Images/CurveFit1.png
https://www.seventransistorlabs.com/Images/CurveFit2.png
The half-corner corresponds to the skin depth of the material (hence the
characteristic sqrt(f) diffusion slope), and the full corner corresponds to
the capacitance between laminations, so, the width and spacing of them.
It's overall better than any ferrite, particularly at low frequencies. And
if you have a lot of noise to handle, Bmax is also much higher. Awesome
stuff.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
P
Piotr Wyderski
Guest
jlarkin@highlandsniptechnology.com wrote:
> Looks like drum cores might work:
I've also used a drum. If you fill this with TIW 1mm, you'll get 250uH.
This is 42mm in diameter, is it big? Don't know your criteria.
https://www.tme.eu/pl/en/details/cp-p42_29/coil-formers-and-accessories/ferroxcube/
About the size of mine and the saturation current is only 6.5A.
Is it worth playing with the ferrite at all? Double the number
of turns of mine and you'll get your 1mH.
All non-air core ones are like this. Alloy powder are particularly
notorious, but it is not a problem, if you design taking it into
account. My last PSU uses one with 4:1 swing and this is even an advantage.
Best regards, Piotr
> Looks like drum cores might work:
I've also used a drum. If you fill this with TIW 1mm, you'll get 250uH.
This is 42mm in diameter, is it big? Don't know your criteria.
https://www.tme.eu/pl/en/details/cp-p42_29/coil-formers-and-accessories/ferroxcube/
About the size of mine and the saturation current is only 6.5A.
Is it worth playing with the ferrite at all? Double the number
of turns of mine and you'll get your 1mH.
All non-air core ones are like this. Alloy powder are particularly
notorious, but it is not a problem, if you design taking it into
account. My last PSU uses one with 4:1 swing and this is even an advantage.
Best regards, Piotr
J
John Larkin
Guest
On Sat, 17 Aug 2019 09:31:05 -0700, jlarkin@highlandsniptechnology.com
wrote:
Working with one 2.5 mH coil of the Schaffner inductor, it loses about
half its inductance at 90 mA DC. Not good enough for my application,
but still an interesting part.
As a pulse transformer, 50:50 ohm rise time is about 200 ns! Could be
a gate driver.
wrote:
Working with one 2.5 mH coil of the Schaffner inductor, it loses about
half its inductance at 90 mA DC. Not good enough for my application,
but still an interesting part.
As a pulse transformer, 50:50 ohm rise time is about 200 ns! Could be
a gate driver.
J
Jan Panteltje
Guest
On a sunny day (Mon, 19 Aug 2019 10:22:20 -0700) it happened John Larkin
<jlarkin@highland_atwork_technology.com> wrote in
<12mlledvimvb209p2q7k7mnrc11nttpgv6@4ax.com>:
they make pulse transformers etc..
https://www.schaffner.com/nc/products/configurator/
<jlarkin@highland_atwork_technology.com> wrote in
<12mlledvimvb209p2q7k7mnrc11nttpgv6@4ax.com>:
they make pulse transformers etc..
https://www.schaffner.com/nc/products/configurator/
Guest
On Monday, 19 August 2019 15:05:53 UTC+1, Bill Sloman wrote:
time wasting idiot plonked
time wasting idiot plonked
B
Bill Sloman
Guest
On Tuesday, August 20, 2019 at 8:26:34 AM UTC+10, tabb...@gmail.com wrote:
<snip>
NT doesn't like being outed as a twit.
--
Bill Sloman, Sydney
<snip>
NT doesn't like being outed as a twit.
--
Bill Sloman, Sydney
P
Piotr Wyderski
Guest
Tim Williams wrote:
My measurements of the 16mm cores indicate about this saturation
current, so it is an experimentally confirmed value.
> There's also square B-H varieties for magamp use.
Have never been able to buy one for prototyping.
The 3R1 is all I have, but my experiments show
that low-signal magamps work tollerably well even
with normal ferrites like the F938. Very forgiving
technology.
> The half-corner corresponds to the skin depth of the material
Oh, so *that* is the reason! Makes sense, thanks!
Best regards, Piotr
My measurements of the 16mm cores indicate about this saturation
current, so it is an experimentally confirmed value.
> There's also square B-H varieties for magamp use.
Have never been able to buy one for prototyping.
The 3R1 is all I have, but my experiments show
that low-signal magamps work tollerably well even
with normal ferrites like the F938. Very forgiving
technology.
> The half-corner corresponds to the skin depth of the material
Oh, so *that* is the reason! Makes sense, thanks!
Best regards, Piotr
J
Jan Panteltje
Guest
On a sunny day (Tue, 20 Aug 2019 09:28:34 +0200) it happened Piotr Wyderski
<peter.pan@neverland.mil> wrote in <qjg7dq$7n3$1@gioia.aioe.org>:
Magamps or 'transductors' were in practially every old CRT based color set over here.
There should be zilions around in the old TV dump,
Philips used those in their color sets, holds some patents.....
Those were used to correct the horizontal deflection amplitude
'pin cussion' distortion.
So they regulated the 15625 Hz(Europe) scan amplitude,
and were controlled by the 50 Hz (Europe) vertical scan.
(Use different frequencies for US.)
https://4.bp.blogspot.com/-dow1s92HswE/WiKB_vuRe2I/AAAAAAAAaJk/nxI7wmhMWIQJVmK57sq51IUd9mqo0pF2ACK4BGAYYCw/s320/ITT-THYRISTOR-DEFL-FIG6__TVMS.jpg
<peter.pan@neverland.mil> wrote in <qjg7dq$7n3$1@gioia.aioe.org>:
Magamps or 'transductors' were in practially every old CRT based color set over here.
There should be zilions around in the old TV dump,
Philips used those in their color sets, holds some patents.....
Those were used to correct the horizontal deflection amplitude
'pin cussion' distortion.
So they regulated the 15625 Hz(Europe) scan amplitude,
and were controlled by the 50 Hz (Europe) vertical scan.
(Use different frequencies for US.)
https://4.bp.blogspot.com/-dow1s92HswE/WiKB_vuRe2I/AAAAAAAAaJk/nxI7wmhMWIQJVmK57sq51IUd9mqo0pF2ACK4BGAYYCw/s320/ITT-THYRISTOR-DEFL-FIG6__TVMS.jpg
T
Tim Williams
Guest
"Piotr Wyderski" <peter.pan@neverland.mil> wrote in message
news:qjg7dq$7n3$1@gioia.aioe.org...
You may have some and not know it! The old school ATX power supplies
derived the 3.3V supply from the transformer's 5V taps, using one tap
directly and the other tap controlled with a magamp and TL431. That's why
the 3.3V is so damn accurate (within 10s of mV) while everything else is a
sausage!
Typically the component is black ferrite, or plastic-cased nanocrystalline
strip, 4-5 turns, and may be wrapped in heat-shrink.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
news:qjg7dq$7n3$1@gioia.aioe.org...
You may have some and not know it! The old school ATX power supplies
derived the 3.3V supply from the transformer's 5V taps, using one tap
directly and the other tap controlled with a magamp and TL431. That's why
the 3.3V is so damn accurate (within 10s of mV) while everything else is a
sausage!
Typically the component is black ferrite, or plastic-cased nanocrystalline
strip, 4-5 turns, and may be wrapped in heat-shrink.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
P
Piotr Wyderski
Guest
Tim Williams wrote:
That's most likely the 3R1:
https://ferrite.qutic.com/pdf/3r1.pdf
I would not expect a nanocrystaline ribbon in a Chinese PSU. Would
probaby constitute a half of its price. :->
Best regards, Piotr
That's most likely the 3R1:
https://ferrite.qutic.com/pdf/3r1.pdf
I would not expect a nanocrystaline ribbon in a Chinese PSU. Would
probaby constitute a half of its price. :->
Best regards, Piotr
T
Tim Williams
Guest
"Piotr Wyderski" <peter.pan@neverland.mil> wrote in message
news:qjhghi$19v$1@gioia.aioe.org...
Maybe. Or maybe the supplies I took apart weren't sourced from China, who
knows. Here's a few, with some other specimens for reference:
https://www.seventransistorlabs.com/Images/FerritesAndMagamps.jpg
I don't think I have any square ferrites in here (actually, I probably do,
but haven't measured them to be sure, and none that are obviously gooped
with varnish), but I have a few beheatshrinked inductors in another box that
appear to be ferrite, most likely the 3R1 or something closely related.
I've seen both, definitely.
The amorphous/nanocrystalline cores can be easy to miss; the black one is
thick and square and has a middle seam, but could easily be mistaken at a
glance for black ferrite, especially with the varnish gooped on it.
That's probably a 15k mu ferrite, top left. Apparently they'll put ferrites
in plastic boxes too (presumably for the creepage distance to core?). So I
included that too, without the box obviously.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
news:qjhghi$19v$1@gioia.aioe.org...
Maybe. Or maybe the supplies I took apart weren't sourced from China, who
knows. Here's a few, with some other specimens for reference:
https://www.seventransistorlabs.com/Images/FerritesAndMagamps.jpg
I don't think I have any square ferrites in here (actually, I probably do,
but haven't measured them to be sure, and none that are obviously gooped
with varnish), but I have a few beheatshrinked inductors in another box that
appear to be ferrite, most likely the 3R1 or something closely related.
I've seen both, definitely.
The amorphous/nanocrystalline cores can be easy to miss; the black one is
thick and square and has a middle seam, but could easily be mistaken at a
glance for black ferrite, especially with the varnish gooped on it.
That's probably a 15k mu ferrite, top left. Apparently they'll put ferrites
in plastic boxes too (presumably for the creepage distance to core?). So I
included that too, without the box obviously.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/