Driver to drive?

[Szczepan Białek]

"Szczepan Białek" <sz.bialek@wp.pl> wrote
news:gaq81n$9m0$1@node1.news.atman.pl...

Only satellites "plough" eter. Is there any resistance?

"But although it meets the definition of outer space, the atmospheric
density within the first few hundred kilometers above the Kármán line is
still sufficient to produce significant drag on satellites. Most artificial
satellites operate in this region called low earth orbit and must fire their
engines every few days to maintain orbit"
(From: http://en.wikipedia.org/wiki/Vacuum ).

S*

 

[Mike Monett]

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 17 Sep 2008 03:49:58 +0000, Mike Monett <None@here.adr> wrote:

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 16 Sep 2008 23:58:26 +0000, Mike Monett <None@here.adr
wrote:

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 16 Sep 2008 05:54:36 +0000, Mike Monett
None@here.adr> wrote:

[...]

Darn, now you've got me curious. I wish people wouldn't do that.

Why? How can you consider possibilities without curiosity?

ftp://66.117.156.8/VAT-20.zip

That's a Mini-Circuits VAT-20, a cheap 6 GHz, 20 dB attenuator.

The 18 GHz parts are a lot smaller.

What's the schematic look like? The black rectangles look like
thick film resistors. But you can barely see the outline of
something else on the surface. Is that thin-film?

Thickfilm on alumina; screened and fired conductors, screened and
fired cermet resistor elements, laser trimmed.



in >-----+-----R2-------R3------+------< out
| |
| |
R1 R4
| |
| |
| |
gnd>-----+----------------------+------< gnd

The R2-R3 node is a pretty big hunk of conductor, essentially a C to
ground, probably to kill capacitive shoot-through, maybe to
deliberately limit the bw to 6 GHz.

A la Winfield's high voltage probe. But the thick film will also have
a built-in frequency limit due to skin effect, as described in the
Microwaves 101 web page.

You said the 18 GHz parts are smaller. What do they look like?

Ask Mr Google.

John

Thanks, John. That's money in the bank.

Mike Monett

 

[john jardine]

"Helmut Sennewald" <helmutsennewald@t-online.de> wrote in message
news:garftc$rt7$01$1@news.t-online.com...

"john jardine" <john.jardine@idnet.co.uk> schrieb im Newsbeitrag
news:RHVzk.60287$ym1.37052@en-nntp-09.am2.easynews.com...

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:f1Vzk.498$x%.5@nlpi070.nbdc.sbc.com...
Ok, simple circuit: Schmitt inverter, 10K resistor from output to
input,
1000pF capacitor from input to ground. Vh set to about 20% of Vhigh.
Should happily oscillate but I get the error message "Time step too
small". Also there is a noted dip in voltage down to about 80%,
something which should even be possible with a digital behavioral
device.

What gives? How can I fix that and make it run? Does it need some kind
of kicker?

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Add something like "vhigh=5 trise=10n". Essentially the 'trise' adds a
bit
of time reality to the gate. The help file is particularly obtuse in
this
area. I've still to discover what that "ref" thing is there for.


Hello,

"ref" is the threshold for normal digital devices like AND and OR.
If you don't specify "ref", it's (vhigh+vlow)/2

The threshold for Schmitt trigger devices is "vt" and "vh", but not "ref".

Helmut

Got that. Thanks Helmut.

I really like the program, make extensive use of it and slowly but surely,
am getting there bit by bit. The 'bit by bit' bit due to an ongoing
cultural struggle, with Mike's impenetrable 'help' descriptions.
Would love to see these rewritten by a non programmer into something like
English (or French or German or Swahili, I don't mind, the translation would
be staightforward
Maybe someday I'll then get to use that (good) saturating core model that
I've seen occasional mysterious references to.

 

[Damon Hill]

RichD <r_delaney2001@yahoo.com> wrote in news:b78fc9c2-fe9c-444c-8ac5-
606090de2aba@p31g2000prf.googlegroups.com:

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

They do? Seems like it's possible to design good amplifiers either
way.

--Damon

 

[Trevor Wilson]

"RichD" <r_delaney2001@yahoo.com> wrote in message
news:b78fc9c2-fe9c-444c-8ac5-606090de2aba@p31g2000prf.googlegroups.com...

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

**Non-sequitur. If you're saying that MOSFET outputs sound better, they
don't.

As a device, operating at typical bias currents (say) 10-50mA, MOSFETs
exhibit VASTLY more THD than BJTs. Only when bias currents are elevated
(around 0.5A - 1A) do MOSFETs exhibit THD characteristics which are almost
as good as BJTs.

MOSFETs are very tough, have an exceptional ability to deliver high power,
high frequency audio (and RF), but distortion is very high. They require
lots of Global NFB in order to operate linearly.

MOSFETs do not sound better than BJTs. At best, they can sound as good. All
things being equal.


--
Trevor Wilson
www.rageaudio.com.au

 

[Phil Allison]

"Trevor Wilson"
"RichD"

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

**Non-sequitur. If you're saying that MOSFET outputs sound better, they
don't.

As a device,

** Same old red-herring BOLLOCKS from know nothing Wilson.

It is totally irrelevant how DEVICES behave on their own.

Only when they are properly configured and suitably biased in a
complimentary output stage can performances be compared.


operating at typical bias currents (say) 10-50mA, MOSFETs

exhibit VASTLY more THD than BJTs.

** UTTER BOLLOCKS !!!

When configured in typical amplifier topologies, THD is vanishingly small at
all power levels and with minimal bias current.

This is true for LATERAL mosfets as made by Hitachi and Semelab ( ie 2SK176,
BUZ905 etc ).

Switching mosfets ( ie IRFPxxx etc) are not the same.



...... Phil

 

[Nico Coesel]

"km@mathcs.emory.edu" <km@mathcs.emory.edu> wrote:

I measured the power consumption of a computer at 140 watts using a
'killowatt" power meter. Then I plugged the computer into my Belkin
UPS and measured the increase in power drawn by the UPS at 200 watts.

Is the extra 60 watt penalty expected?

No. But perhaps the UPS is charging its batteries. A low cost UPS
should not consume more than a few watts when idle.

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

 

[Jorden Verwer]

RichD wrote:

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

The device properties of BJTs are superior to those of MOSFETs in all
respects, except for offset - there MOSFETs have the advantage. Whether you
will actually hear this depends on many more factors.

 

[Gareth Magennis]

"RichD" <r_delaney2001@yahoo.com> wrote in message
news:b78fc9c2-fe9c-444c-8ac5-606090de2aba@p31g2000prf.googlegroups.com...

Who do MOSFET sound better than bipolar, as an audio amp output
driver?


--
Rich

Well this is probably an urban myth/load of bollocks, but years ago lots of
people were talking about power Mosfets exhibiting different distortion
characteristics than BJT's in the same way thermionic valves distort with
differening harmonics and sound nicer.

Fact or crapology?



Gareth.

 

[Trevor Wilson]

"Kevin McMurtrie" <kevinmcm@sonic.net> wrote in message
news:kevinmcm-9B2679.00003118092008@C-61-68-245-199.per.connect.net.au...

In article <6je37eF2sms3U1@mid.individual.net>,
"Trevor Wilson" <trevor@_SPAMBLOCK_rageaudio.com.au> wrote:

"RichD" <r_delaney2001@yahoo.com> wrote in message
news:b78fc9c2-fe9c-444c-8ac5-606090de2aba@p31g2000prf.googlegroups.com...
Who do MOSFET sound better than bipolar, as an audio amp output
driver?

**Non-sequitur. If you're saying that MOSFET outputs sound better, they
don't.

As a device, operating at typical bias currents (say) 10-50mA, MOSFETs
exhibit VASTLY more THD than BJTs. Only when bias currents are elevated
(around 0.5A - 1A) do MOSFETs exhibit THD characteristics which are
almost
as good as BJTs.

MOSFETs are very tough, have an exceptional ability to deliver high
power,
high frequency audio (and RF), but distortion is very high. They require
lots of Global NFB in order to operate linearly.

That's nonsense.

**Er, nope. Here are the specs for a modern high power BJT:

http://www.toshiba.com/taec/components2/Datasheet_Sync//66/7890.pdf

Note the hFE vs. Ic. Particularly at elevated temps. It is almost a straight
line, from less than 10mA to several Amps. I call that spectacular
linearity.

Now, I draw your attention to a high power MOSFET:

http://www.magnatec-uk.com/pdf/magnatec/BUZ900.pdf

Note the characteristics of this device. They're pretty good, but as good as
a modern BJT.

Here is another, older, worse example:

http://www.datasheetarchive.com/pdf-datasheets/Datasheets-8/DSA-158541.html

Quite ordinary lineariy.

MOSFETs have a lower voltage gain, more capacitive

load, and infinite DC current gain. If you swap your bipolar
transistors for MOSFETs and crank up the bias voltage, yeah, it will run
like crap because the local feedback gain is totally wrong.

**I never suggested anything of the sort. I mentioned ONLY the intrinsic
linearity of the devices. MOSFETs are inferior to BJTs. For now. When
installed in an appropriate topology, it is likely that there will be little
audible, nor measurable difference between a MOSFET amp and a BJT amp.
Device linearity is another story.

It might

even incapacitate every radio within two blocks of your home then
violently explode. The circuits to drive MOSFETs and bipolars are a
little different.

**Again, not in dispute. The intrinsic linearity, is what I refer to.


--
Trevor Wilson
www.rageaudio.com.au

 

[Phil Allison]

"Randy Yates"

"Phil Allison"

**Non-sequitur. If you're saying that MOSFET outputs sound better, they
don't.

As a device,


** Same old red-herring BOLLOCKS from know nothing Wilson.

It is totally irrelevant how DEVICES behave on their own.

Only when they are properly configured and suitably biased in a
complimentary output stage can performances be compared.


operating at typical bias currents (say) 10-50mA, MOSFETs
exhibit VASTLY more THD than BJTs.


** UTTER BOLLOCKS !!!

No it's not.

** Yes it is you pathetic, know nothing MORON,

When configured in typical amplifier topologies, THD is vanishingly small
at
all power levels and with minimal bias current.

That may be true, but only because of the negative feedback that Trevor
referred to.

** Bull.

The basic device IS more nonlinear.

** Irrelevant.

Can't you read - dickhead.



..... Phil

 

[Gareth Magennis]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:48D22861.F271B0C4@hotmail.com...

Gareth Magennis wrote:

"RichD" <r_delaney2001@yahoo.com> wrote

Who do MOSFET sound better than bipolar, as an audio amp output
driver?

Well this is probably an urban myth/load of bollocks, but years ago lots
of
people were talking about power Mosfets exhibiting different distortion
characteristics than BJT's in the same way thermionic valves distort with
differening harmonics and sound nicer.

Fact or crapology?

Fact. Different transfer characteristics. Fundamental device physics.

Graham

Well in that case the OP's question is thus answered, as far as I can tell.
It sure is noisy in here.



Gareth.

 

[Phil Allison]

"Gareth Magennis"

Well this is probably an urban myth/load of bollocks, but years ago lots
of people were talking about power Mosfets exhibiting different distortion
characteristics than BJT's in the same way thermionic valves distort with
differening harmonics and sound nicer.

Fact or crapology?

** Audiophool crapology - repeated parrot fashion, ad nauseam.

The THD residual of even the simplest topology, lateral mosfet audio
amplifiers is vanishingly small.

Sub the threshold of audibility.



..... Phil

 

[Phil Allison]

"Gareth Magennis"

Well in that case the OP's question is thus answered, as far as I can
tell.

** It can never be answered.

Since it was a UTTERLY meaningless TROLL.

You pathetic fool.




..... Phil

 

[TheM]

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:8um3d4hvrf8ivn38q9vkj0ten945j24shv@4ax.com...

http://english.pravda.ru/opinion/columnists/106313-0/


John

This one is even more far fetched. Billions of watts on a table-top.
Probably in a nanosecond pulse.
http://english.pravda.ru/science/tech/04-09-2008/106296-electromagnetic_super_weapon-0

M

 

[Gareth Magennis]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6jep4lF2vrv3U1@mid.individual.net...

"Gareth Magennis"


Well this is probably an urban myth/load of bollocks, but years ago lots
of people were talking about power Mosfets exhibiting different
distortion characteristics than BJT's in the same way thermionic valves
distort with differening harmonics and sound nicer.

Fact or crapology?


** Audiophool crapology - repeated parrot fashion, ad nauseam.

The THD residual of even the simplest topology, lateral mosfet audio
amplifiers is vanishingly small.

Sub the threshold of audibility.



.... Phil

Not if you clip them like you might a valve amp for example. Would a Mosfet
amp clip more "nicely" than a BJT amp? I'm thinking driving bass speakers.
Is this what some of these "audiophools" or pehaps PA guys are getting at by
saying they sound better?



Gareth.

 

[Phil Allison]

"Gareth Magennis"

"Phil Allison"

Well this is probably an urban myth/load of bollocks, but years ago lots
of people were talking about power Mosfets exhibiting different
distortion characteristics than BJT's in the same way thermionic valves
distort with differening harmonics and sound nicer.

Fact or crapology?


** Audiophool crapology - repeated parrot fashion, ad nauseam.

The THD residual of even the simplest topology, lateral mosfet audio
amplifiers is vanishingly small.

Sub the threshold of audibility.


Not if you clip them like you might a valve amp for example.

** Only fucking half-wits listen to clipped audio from a home hi-fi.

Would a Mosfet amp clip more "nicely" than a BJT amp?

** No.

Any more fuckwit MOSFET myths you want to give an airing here ?

Imbecile.



...... Phil

 

[Gareth Magennis]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6jeq47F2unohU1@mid.individual.net...

"Gareth Magennis"
"Phil Allison"

Well this is probably an urban myth/load of bollocks, but years ago
lots of people were talking about power Mosfets exhibiting different
distortion characteristics than BJT's in the same way thermionic valves
distort with differening harmonics and sound nicer.

Fact or crapology?


** Audiophool crapology - repeated parrot fashion, ad nauseam.

The THD residual of even the simplest topology, lateral mosfet audio
amplifiers is vanishingly small.

Sub the threshold of audibility.


Not if you clip them like you might a valve amp for example.


** Only fucking half-wits listen to clipped audio from a home hi-fi.


Would a Mosfet amp clip more "nicely" than a BJT amp?


** No.

Any more fuckwit MOSFET myths you want to give an airing here ?

Imbecile.



..... Phil

Er, perhaps. Mosfets don't have the same thermal characteristics as BJT's,
which are more prone to thermal runaway. So perhaps when you are runing
Mosfets hard, there is some kind of compression thing going on which sounds
nicer than a BJT amp exploding after clipping a lot.




Gareth.

 

[Phil Allison]

"Gareth Magennis"

"Phil Allison"


Not if you clip them like you might a valve amp for example.


** Only fucking half-wits listen to clipped audio from a home hi-fi.


Would a Mosfet amp clip more "nicely" than a BJT amp?


** No.

Any more fuckwit MOSFET myths you want to give an airing here ?

Imbecile.


Er, perhaps.

** Wot a glutton for punishment we have here - folks.

Mosfets don't have the same thermal characteristics as BJT's, which are
more prone to thermal runaway. So perhaps when you are runing Mosfets
hard, there is some kind of compression thing going on which sounds nicer
than a BJT amp exploding after clipping a lot.

** Another 100% fuckwit MOSFET myth.............

Go away - you IDIOT !!!



....... Phil

 

[Gareth Magennis]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:48D239BC.D6F98FC9@hotmail.com...

Gareth Magennis wrote:

Er, perhaps. Mosfets don't have the same thermal characteristics as
BJT's,
which are more prone to thermal runaway. So perhaps when you are runing
Mosfets hard, there is some kind of compression thing going on which
sounds
nicer than a BJT amp exploding after clipping a lot.

Competently designed BJT amps don't 'explode'. It's not difficult, but the
Chinese haven't quite mastered it yet.

Graham

The point is that when people prefer one amp over another it may not be easy
to tell technically what it is they prefer. If a Mosfet amp compresses the
bottom end slightly over a BJT, for example, this might in the long term be
a nicer sounding amp. Maybe absolutely nothing to do with crossover
distorion, linearity, feedback blah blah blah.



Gareth.