Driver to drive?

[Joerg]

Phil Hobbs wrote:

Joerg wrote:
Phil Hobbs wrote:
Jan Panteltje wrote:
On a sunny day (Tue, 29 Sep 2009 09:34:08 -0700) it happened Joerg
invalid@invalid.invalid> wrote in
7ier86F30e1vkU1@mid.individual.net>:

UJTs are cool.

Well, yeah, but you probably lived in the Netherlands as a kid. You
guys had dump handelaars and all sorts of electronics places. UJTs
were unobtanium in Germany. Once in a while we'd mount a car and
head over the border. But since I was a kid back then and didn't
have my own car I'd have to hitch a ride. We usually split the cost
for gas and then it was affordable for everyone, but you needed a
whole day.

Later I lived in Zuid Limburg and with a stiff bicycle ride you
could haul stuff home from the surplus dealer in Margraten. Wrecked
many baggage racks that way, plus some chains, axles and so on. And
found out the hard way that bicycle brakes don't work so good with
50 pounds of stuff on the back.

Still widely available, I used the 2N2646:
http://nl.farnell.com/unijunction-transistors-ujt

I like PUTs for things like laser interlocks. Unlike ICs, I know
exactly how they'll behave in fault conditions, which matters a lot.
Relays are good too.


Thanks. AFAICT the 2646 has long since been obsoleted, maybe still
considered by boutique mfgs. When I was young I was always told "We
can order it but that'll really cost ya". I didn't know you could
still get the 6027 although the fact that it was never migrated to SMT
doesn't bode well for its future.

Personally I have never seen a design that contained a UJT, this
technology may have played chicken and egg for too long.


For my purposes the two-BJT SCR works fine too. Doesn't have to be
fast, just very reliable and predictable.

If I need a crowbar or something to that effect I usually take a regular
SCR, a TL431, a transistor and some resistors. You can make that go off
at rather precise levels. Impressed a client quite a bit who was used to
the regular sloppy crowbars. I told them mine would trigger between 3.6V
and 3.7V. "Really?" ... "Yeah". It triggered at precisely 3.65V

--
Regards, Joerg

http://www.analogconsultants.com/

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

 

[Rene Tschaggelar]

John Larkin wrote:

On Tue, 29 Sep 2009 11:22:32 +0200, Rene Tschaggelar <none@none.net
wrote:

Jim Thompson wrote:
Anyone have clever ideas for rectifying a 500MHz sine wave, amplitude
say 50mV to 500mV peak-to-peak?

Half wave is OK.

1mV accuracy is needed :-(

Process is X-Fab XB06.

Thanks!

...Jim Thompson
There are zero-bias diodes available up to at
least Xband (10GHz). They have a sensitivity
of in the order of -55dBm

I recently got some for 30 bucks each.

Rene

Try Skyworks. Similar parts for under a buck.

John

Thanks John,
we then took some M/A-Com parts. It was to be mounted
into a waveguide in the DO119 case. I'll have a look
at skyworks for next time. They deliver through BFI
Optilas and possibly digikey.

Rene

 

[Jim Thompson]

On Tue, 29 Sep 2009 12:56:53 -0700, Joerg <invalid@invalid.invalid>
wrote:

Phil Hobbs wrote:
Joerg wrote:
Phil Hobbs wrote:
Jan Panteltje wrote:
On a sunny day (Tue, 29 Sep 2009 09:34:08 -0700) it happened Joerg
invalid@invalid.invalid> wrote in
7ier86F30e1vkU1@mid.individual.net>:

UJTs are cool.

Well, yeah, but you probably lived in the Netherlands as a kid. You
guys had dump handelaars and all sorts of electronics places. UJTs
were unobtanium in Germany. Once in a while we'd mount a car and
head over the border. But since I was a kid back then and didn't
have my own car I'd have to hitch a ride. We usually split the cost
for gas and then it was affordable for everyone, but you needed a
whole day.

Later I lived in Zuid Limburg and with a stiff bicycle ride you
could haul stuff home from the surplus dealer in Margraten. Wrecked
many baggage racks that way, plus some chains, axles and so on. And
found out the hard way that bicycle brakes don't work so good with
50 pounds of stuff on the back.

Still widely available, I used the 2N2646:
http://nl.farnell.com/unijunction-transistors-ujt

I like PUTs for things like laser interlocks. Unlike ICs, I know
exactly how they'll behave in fault conditions, which matters a lot.
Relays are good too.


Thanks. AFAICT the 2646 has long since been obsoleted, maybe still
considered by boutique mfgs. When I was young I was always told "We
can order it but that'll really cost ya". I didn't know you could
still get the 6027 although the fact that it was never migrated to SMT
doesn't bode well for its future.

Personally I have never seen a design that contained a UJT, this
technology may have played chicken and egg for too long.


For my purposes the two-BJT SCR works fine too. Doesn't have to be
fast, just very reliable and predictable.


If I need a crowbar or something to that effect I usually take a regular
SCR, a TL431, a transistor and some resistors. You can make that go off
at rather precise levels. Impressed a client quite a bit who was used to
the regular sloppy crowbars. I told them mine would trigger between 3.6V
and 3.7V. "Really?" ... "Yeah". It triggered at precisely 3.65V

From the late '70's onward I've probably used as many TL431's as
OpAmps... the world's most "peppy" NPN ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Coming soon to the elementary school in your neighborhood...

I pledge allegiance to Dear Leader Barack Hussein Obama and to the
community organization for which he stands: one nation under
ACORN, unchallengeable, with wealth redistribution and climate
change for all.

 

[Joerg]

Jim Thompson wrote:

On Tue, 29 Sep 2009 12:56:53 -0700, Joerg <invalid@invalid.invalid
wrote:

Phil Hobbs wrote:
Joerg wrote:
Phil Hobbs wrote:
Jan Panteltje wrote:
On a sunny day (Tue, 29 Sep 2009 09:34:08 -0700) it happened Joerg
invalid@invalid.invalid> wrote in
7ier86F30e1vkU1@mid.individual.net>:

UJTs are cool.
Well, yeah, but you probably lived in the Netherlands as a kid. You
guys had dump handelaars and all sorts of electronics places. UJTs
were unobtanium in Germany. Once in a while we'd mount a car and
head over the border. But since I was a kid back then and didn't
have my own car I'd have to hitch a ride. We usually split the cost
for gas and then it was affordable for everyone, but you needed a
whole day.

Later I lived in Zuid Limburg and with a stiff bicycle ride you
could haul stuff home from the surplus dealer in Margraten. Wrecked
many baggage racks that way, plus some chains, axles and so on. And
found out the hard way that bicycle brakes don't work so good with
50 pounds of stuff on the back.
Still widely available, I used the 2N2646:
http://nl.farnell.com/unijunction-transistors-ujt
I like PUTs for things like laser interlocks. Unlike ICs, I know
exactly how they'll behave in fault conditions, which matters a lot.
Relays are good too.

Thanks. AFAICT the 2646 has long since been obsoleted, maybe still
considered by boutique mfgs. When I was young I was always told "We
can order it but that'll really cost ya". I didn't know you could
still get the 6027 although the fact that it was never migrated to SMT
doesn't bode well for its future.

Personally I have never seen a design that contained a UJT, this
technology may have played chicken and egg for too long.

For my purposes the two-BJT SCR works fine too. Doesn't have to be
fast, just very reliable and predictable.

If I need a crowbar or something to that effect I usually take a regular
SCR, a TL431, a transistor and some resistors. You can make that go off
at rather precise levels. Impressed a client quite a bit who was used to
the regular sloppy crowbars. I told them mine would trigger between 3.6V
and 3.7V. "Really?" ... "Yeah". It triggered at precisely 3.65V

From the late '70's onward I've probably used as many TL431's as
OpAmps... the world's most "peppy" NPN ;-)

Same here. I always wanted one in PNP flavor. IIRC there was (is?) a
National part but it was expensive so I always sprung for another NPN
behind the TL431.

--
Regards, Joerg

http://www.analogconsultants.com/

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

 

[whit3rd]

On Sep 26, 4:47 pm, George <quinton.l...@gmail.com> wrote:

I measured some 1206 SMD COG caps, 1nF 50V, over temperature, Very
stable -40 to +90C, well within spec of 5%, I got about 1%. The caps
were slodered to thin flying leads.

Next test was on a board, things are a lot worse, most made expansion
the spec but only just. The problem we had already identified as board
expansion stressing the caps.

Thinner boards
Strategically drilled holes,
Raisinig the caps slightly to reduce leverage

It looks like you have the problem nailed; if/when the parts
manufacturers
want to sell their parts as higher-precision, they'll solve some of
these
issues, but anything you do at your end will just be a stopgap until
the manufacturer takes their next manufacturing-change step.

Many ceramics with good high dielectric values are piezoelectric, will
respond to stress. Mounting them to a special substrate that has less
thermal mismatch, then soldering to the substrate, can work (it's
how Hall sensors are made, for similar reasons), but it's costly.
Strategic holes, or slots, in thin boards is a good trick, also
costly.

The only thing you can do that's not extra expense, is to change the
mounting pads for the surface-mount artwork; it's possible that
a bit of reshaping can change the local board flexure or buckling
enough to improve the performance. Your fabricator, and the
capacitor manufacturer, will then insist that any problems that
arise are your "fault", of course.

Bell Labs/Western Electric was a conglomerate that could investigate
and solve such problems; NASA could do it, too. Little outfits
solving problems on a this-week-or-never basis just have to put
up with the irritation.

 

[Jan Panteltje]

On a sunny day (Tue, 29 Sep 2009 13:29:48 -0400) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<lvqdnVZytI2N2V_XnZ2dnUVZ_rOdnZ2d@supernews.com>:

I like PUTs for things like laser interlocks. Unlike ICs, I know
exactly how they'll behave in fault conditions, which matters a lot.
Relays are good too.

Cheers

Phil Hobbs

I have never used PUTs, think I have some in the box though.
I liked the UJTs so much because if you made a RC oscillator with those,
then the frequency would be independent of the supply voltage.
This because the intrinsic standoff ratio is fixed at say about 0.6.
Later the 555 timer appeared, with f also independent of supply voltage...
I kept using UJTs.
They were easy to sync too.

 

[John Larkin]

On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid>
wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 13:34:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 09:25:15 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 17:43:22 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 20:05:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Mon, 28 Sep 2009 10:25:05 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:58:27 -0700, Archimedes' Lever
OneBigLever@InfiniteSeries.Org> wrote:

On Sat, 26 Sep 2009 16:52:40 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:28:50 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:
There's the slideback technique: drive a comparator with RF on one
side, DC feedback on the other. Tease the DC appropriately.

I once made a slideback sampling oscilloscope, using tunnel diodes, as
my EE senior project. I won an award and had to attend a dreadful IEEE
chapter banquet and repeat it to a bunch of old-fart power engineers
who didn't understand a word I said. I described the slideback
sampling scope in this ng some years back and a certain party loved
the idea so much he later decided that he'd invented it himself.
http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html
TDs are insanely expensive nowadays, ballpark $100. I used to get them
for a couple bucks from Allied. The fabrication process is insane, and
nobody ever modernized it.

There are some more modern planar germanium back diodes, essentially
low Ip tunnel diodes, but they're RF detectors, useless for switching.
Pity, I used to like tunnel diodes.

http://aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf

John
Try PiN diodes then.
For what? Certainly not switching, amplifying, oscillating, detection,
or mixing.
---
Re. switching, From:

http://en.wikipedia.org/wiki/PIN_diode

"Under zero or reverse bias, a PIN diode has a low capacitance. The low
capacitance will not pass much of an RF signal. Under a forward bias of
1 mA, a typical PIN diode will have an RF resistance of about 1 ohm,
making it a good RF conductor. Consequently, the PIN diode makes a good
RF switch."
---
Good, but not fast. PIN diodes specialize in having a lot of stored
charge, so that the signal current can be quite a bit larger than the DC
current without causing excessive distortion.

Cheers

Phil Hobbs
PINs stop behaving like PINs at low frequencies, too. So they don't
make useful wideband switches.

Got to watch the carrier lifetime. The lower the bottom of your spectrum
and the higher the RF current, the longer its carrier lifetime must be.
I found PIN diodes to be great and most of all cheap variable
attenuators as well as switched. Designed in tons of them.


But I meant active switching when I was referring to a TD. A TD would
*generate* a fast step from an arbitrarily slow drive.

I've drooled over SRDs all my life and every time I wanted to buy one I
either couldn't have one or it was outlandishly expensive. Guess
avalanching is the only game in town and if you want avalanche-rated
then a bone-simple BJT can easily shoot up to twenty bucks.
SRDs aren't hard to get. MA/Com has distributor parts, under a buck.
M-Pulse and Metelics are good about samples. If you want a few, send
me a SASE.

Oh, here it is...

229-1769 DIO SRD 30V SOT23 150PS MA44769 1PF

MA44769-287 PENSTOCK

Price 58 cents in small quantities.

They also have MA44767-287, 600 ps risetime, a little easier to drive
because it stores more charge.

These make nice edge generators and frequency multipliers. I have a
rubidium clock that generates the 6.3846826128 GHz frequency from a 10
MHz rock with an absurdly small number of cheap parts.

Thanks, John! That's a decent price. And thanks for the SASE offer, but
maybe I'll combine that with a beer at Zeitgeist when I get down there
Well, drop in. We have a zillion exotic parts in stock. And the
quality of Z's burgers has improved radically lately. Only biker bar I
know of with Chimay on tap.

As a kid I grew up in Europe and back then such exotic parts were very
hard to find over there, even at hamfests.
We were lucky. Tons of exotic surplus gear, lots of old teevees,
Allied and Lafayette and Fair Radio Sales mail-order available to
anyone, local distributors for over-the-counter transistors and
10-turn pots and such... the counter guys gave me more parts than I
ever paid for. I made a deal with my parents to dump my allowance in
favor of a revolving credit account with Allied, so I could just order
stuff. I made spending money fixing radios and TVs.

John

Still not as good as now. I just bought an excellent-condition HP 8568B
spectrum analyzer for $900. About 2 cents on the dollar. So far this
year I've bought test equipment that would have cost way over $100000
new, for probably $4k altogether. Amazing.

Cheers

Phil Hobbs

And I'm looking at, theoretically, a quarter million dollars worth of
sampling heads over there on my shelf. This is an amazing time to
start a niche business, or even an exotic hobby.


Is there anything available at reasonable cost that does zippy sampling
without needing a Goliath of a scope attached to it?

Not really. The 5000 and 7000 series scopes had sampling plugins - I
have a bunch, and they're dirt cheap now - but they were pretty bad
compared to the superb 11801-series stuff.

There are some little USB samplers, but they're very expensive.

Pumping scope is good for you.

John

 

[John Larkin]

On Tue, 29 Sep 2009 21:59:41 +0200, Rene Tschaggelar <none@none.net>
wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 11:22:32 +0200, Rene Tschaggelar <none@none.net
wrote:

Jim Thompson wrote:
Anyone have clever ideas for rectifying a 500MHz sine wave, amplitude
say 50mV to 500mV peak-to-peak?

Half wave is OK.

1mV accuracy is needed :-(

Process is X-Fab XB06.

Thanks!

...Jim Thompson
There are zero-bias diodes available up to at
least Xband (10GHz). They have a sensitivity
of in the order of -55dBm

I recently got some for 30 bucks each.

Rene

Try Skyworks. Similar parts for under a buck.

John


Thanks John,
we then took some M/A-Com parts. It was to be mounted
into a waveguide in the DO119 case. I'll have a look
at skyworks for next time. They deliver through BFI
Optilas and possibly digikey.

Rene

They probably don't have the pill-packaged parts. Most of their stuff
is surface mount. We use an SC-79 (practically invisible) 0.2 pF
low-barrier schottky of theirs, SMS7621-079, 38 cents each.

Maybe you can drop a little antenna + diode pc board into the
waveguide?

John

 

[Joerg]

John Larkin wrote:

On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 13:34:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 09:25:15 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 17:43:22 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 20:05:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Mon, 28 Sep 2009 10:25:05 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:58:27 -0700, Archimedes' Lever
OneBigLever@InfiniteSeries.Org> wrote:

On Sat, 26 Sep 2009 16:52:40 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:28:50 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:
There's the slideback technique: drive a comparator with RF on one
side, DC feedback on the other. Tease the DC appropriately.

I once made a slideback sampling oscilloscope, using tunnel diodes, as
my EE senior project. I won an award and had to attend a dreadful IEEE
chapter banquet and repeat it to a bunch of old-fart power engineers
who didn't understand a word I said. I described the slideback
sampling scope in this ng some years back and a certain party loved
the idea so much he later decided that he'd invented it himself.
http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html
TDs are insanely expensive nowadays, ballpark $100. I used to get them
for a couple bucks from Allied. The fabrication process is insane, and
nobody ever modernized it.

There are some more modern planar germanium back diodes, essentially
low Ip tunnel diodes, but they're RF detectors, useless for switching.
Pity, I used to like tunnel diodes.

http://aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf

John
Try PiN diodes then.
For what? Certainly not switching, amplifying, oscillating, detection,
or mixing.
---
Re. switching, From:

http://en.wikipedia.org/wiki/PIN_diode

"Under zero or reverse bias, a PIN diode has a low capacitance. The low
capacitance will not pass much of an RF signal. Under a forward bias of
1 mA, a typical PIN diode will have an RF resistance of about 1 ohm,
making it a good RF conductor. Consequently, the PIN diode makes a good
RF switch."
---
Good, but not fast. PIN diodes specialize in having a lot of stored
charge, so that the signal current can be quite a bit larger than the DC
current without causing excessive distortion.

Cheers

Phil Hobbs
PINs stop behaving like PINs at low frequencies, too. So they don't
make useful wideband switches.

Got to watch the carrier lifetime. The lower the bottom of your spectrum
and the higher the RF current, the longer its carrier lifetime must be.
I found PIN diodes to be great and most of all cheap variable
attenuators as well as switched. Designed in tons of them.


But I meant active switching when I was referring to a TD. A TD would
*generate* a fast step from an arbitrarily slow drive.

I've drooled over SRDs all my life and every time I wanted to buy one I
either couldn't have one or it was outlandishly expensive. Guess
avalanching is the only game in town and if you want avalanche-rated
then a bone-simple BJT can easily shoot up to twenty bucks.
SRDs aren't hard to get. MA/Com has distributor parts, under a buck.
M-Pulse and Metelics are good about samples. If you want a few, send
me a SASE.

Oh, here it is...

229-1769 DIO SRD 30V SOT23 150PS MA44769 1PF

MA44769-287 PENSTOCK

Price 58 cents in small quantities.

They also have MA44767-287, 600 ps risetime, a little easier to drive
because it stores more charge.

These make nice edge generators and frequency multipliers. I have a
rubidium clock that generates the 6.3846826128 GHz frequency from a 10
MHz rock with an absurdly small number of cheap parts.

Thanks, John! That's a decent price. And thanks for the SASE offer, but
maybe I'll combine that with a beer at Zeitgeist when I get down there
Well, drop in. We have a zillion exotic parts in stock. And the
quality of Z's burgers has improved radically lately. Only biker bar I
know of with Chimay on tap.

As a kid I grew up in Europe and back then such exotic parts were very
hard to find over there, even at hamfests.
We were lucky. Tons of exotic surplus gear, lots of old teevees,
Allied and Lafayette and Fair Radio Sales mail-order available to
anyone, local distributors for over-the-counter transistors and
10-turn pots and such... the counter guys gave me more parts than I
ever paid for. I made a deal with my parents to dump my allowance in
favor of a revolving credit account with Allied, so I could just order
stuff. I made spending money fixing radios and TVs.

John

Still not as good as now. I just bought an excellent-condition HP 8568B
spectrum analyzer for $900. About 2 cents on the dollar. So far this
year I've bought test equipment that would have cost way over $100000
new, for probably $4k altogether. Amazing.

Cheers

Phil Hobbs
And I'm looking at, theoretically, a quarter million dollars worth of
sampling heads over there on my shelf. This is an amazing time to
start a niche business, or even an exotic hobby.

Is there anything available at reasonable cost that does zippy sampling
without needing a Goliath of a scope attached to it?

Not really. The 5000 and 7000 series scopes had sampling plugins - I
have a bunch, and they're dirt cheap now - but they were pretty bad
compared to the superb 11801-series stuff.

There is an 11802 on Ebay right now for $1k but untested, "powers up".
Thing is, I haven't gotten much more space here. A sampler for the 7704
over here would be nice. What is so bad with S-4 and 7S11? Ok, the
25psec risetime doesn't quite rival your gear but for most stuff that
should do.

There are some little USB samplers, but they're very expensive.

Probably not much of a market anymore and the TDR guys in the field
dont' need a precision under a foot to figure where they have to drop
the bucket of their Kubota.

Pumping scope is good for you.

"Room service, good evening. What would you like to order?"

....

"Send up some more room, please."

--
Regards, Joerg

http://www.analogconsultants.com/

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

 

[Paul Hovnanian P.E.]

It takes quite a bit of time and energy to stay wound up about
something. But when I retire, I hope I have better things to do.

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Marching to a different kettle of fish.

 

[krw]

On Tue, 29 Sep 2009 05:54:23 -0700, StickThatInYourPipeAndSmokeIt
<Zarathustra@thusspoke.org> wrote:

On Mon, 28 Sep 2009 20:18:21 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Mon, 28 Sep 2009 21:36:19 -0500, krw <krw@att.bizzzzzzzzzzz> wrote:

On Mon, 28 Sep 2009 18:41:36 -0700, StickThatInYourPipeAndSmokeIt
Zarathustra@thusspoke.org> wrote:

On Mon, 28 Sep 2009 17:53:46 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

Insane

...Jim Thompson

Thompson = zero knowledge of what ESD is.

AlwaysWrong <=> Always wrong.

=== Nymbecile

I've been dealing with ESD and transient issues for ~50 years

...Jim Thompson

Yet you have nothing to contribute to a conversation about
electrostatic event abatement other than a petty, retarded, jack brained
comment followed by a claim of a life long experience with it.

You never have anything to contribute, yet you do anyway.

That would make you the insane one, and the imbecile, you
non-contributory twit.

That would make you AlwaysWrong, Nymcompoop.

 

[Bill Sloman]

On Sep 29, 6:37 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 29 Sep 2009 09:11:36 -0700 (PDT),Bill Sloman

bill.slo...@ieee.org> wrote:
On Sep 29, 2:40 am, dagmargoodb...@yahoo.com wrote:
On Sep 27, 6:37 pm,Bill Sloman<bill.slo...@ieee.org> wrote:

That's not auto calibration, that's just replacing trim pots and screw
drivers with digital pots and an eprom programmer.

Bill you're just being tedious.  Autocalibration is soooo 20th
century--we just don't feel the need to discuss it.  That doesn't mean
we don't do it.

You may do it as a matter of routine, although your personal database
doesn't show much sign of having been up-dated recently. John Larkin
doesn't seem to be entirely at home with the concept.

I'll do whatever works. Lately we've been moving entire nonlinear
channel calibration algorithms into FPGAs. But I'm not "entirely at
home" with building primary standards into measuring instruments, or
taking them offline for self-test or recal without an explicit command
from the user to do so. Even if I could do that transparently, my
customers *really* wouldn't like their gains an offsets being changed
invisibly, mid-run.

John Larkin does waste a lot of time constructing straw men. He makes
one of his typical exaggerated claims, I point that the claim isn't
valid if you put a primary standard inside the instrument, which is
possilbe, if not usual

http://tf.nist.gov/ofm/smallclock/CSAC.html

and he then proceeds to claim that I am advocating putting primary
standards in every instrument.

That's the problem having customers, I guess. It must be be very
liberating to have no customers.

Considering the amount of time you've spent building your straw man
and berating me for adopting a position that you took the trouble to
invent for me, it would seem that you must be running short on
customers at the moment, and are having to find other ways of filling
in your empy days. The anxiety seems to be making you irritable.

Some customers need certified data: confirm cal before a run, take
data, confirm cal after. The idea of continuous calibration is messy
there. The only things you might get away with would be tweaking
dimensionless things, like auto-zero or some such.

Our newer VME modules have a relay per channel and a test connector
(upper D9 in this case)

http://www.highlandtechnology.com/DSS/V450DS.html

so the customer can bus all the test connectors to a
tracable-calibrated DVM or whatever. He can pull in a relay and route
the channel to the cal instrument without disconnecting the field
wiring, making it a software-only thing to verify the cal of the
entire system, every morning if he wants. Why use relays? Because
Pratt&Whitney told us to use relays.

And you couldn't come up with a better alternative.

--
Bill Sloman, Nijmegen

 

[John Larkin]

On Tue, 29 Sep 2009 15:27:53 -0700, Joerg <invalid@invalid.invalid>
wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 13:34:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Tue, 29 Sep 2009 09:25:15 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 17:43:22 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Mon, 28 Sep 2009 20:05:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Fields wrote:
On Mon, 28 Sep 2009 10:25:05 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:58:27 -0700, Archimedes' Lever
OneBigLever@InfiniteSeries.Org> wrote:

On Sat, 26 Sep 2009 16:52:40 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 26 Sep 2009 17:28:50 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:
There's the slideback technique: drive a comparator with RF on one
side, DC feedback on the other. Tease the DC appropriately.

I once made a slideback sampling oscilloscope, using tunnel diodes, as
my EE senior project. I won an award and had to attend a dreadful IEEE
chapter banquet and repeat it to a bunch of old-fart power engineers
who didn't understand a word I said. I described the slideback
sampling scope in this ng some years back and a certain party loved
the idea so much he later decided that he'd invented it himself.
http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html
TDs are insanely expensive nowadays, ballpark $100. I used to get them
for a couple bucks from Allied. The fabrication process is insane, and
nobody ever modernized it.

There are some more modern planar germanium back diodes, essentially
low Ip tunnel diodes, but they're RF detectors, useless for switching.
Pity, I used to like tunnel diodes.

http://aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf

John
Try PiN diodes then.
For what? Certainly not switching, amplifying, oscillating, detection,
or mixing.
---
Re. switching, From:

http://en.wikipedia.org/wiki/PIN_diode

"Under zero or reverse bias, a PIN diode has a low capacitance. The low
capacitance will not pass much of an RF signal. Under a forward bias of
1 mA, a typical PIN diode will have an RF resistance of about 1 ohm,
making it a good RF conductor. Consequently, the PIN diode makes a good
RF switch."
---
Good, but not fast. PIN diodes specialize in having a lot of stored
charge, so that the signal current can be quite a bit larger than the DC
current without causing excessive distortion.

Cheers

Phil Hobbs
PINs stop behaving like PINs at low frequencies, too. So they don't
make useful wideband switches.

Got to watch the carrier lifetime. The lower the bottom of your spectrum
and the higher the RF current, the longer its carrier lifetime must be.
I found PIN diodes to be great and most of all cheap variable
attenuators as well as switched. Designed in tons of them.


But I meant active switching when I was referring to a TD. A TD would
*generate* a fast step from an arbitrarily slow drive.

I've drooled over SRDs all my life and every time I wanted to buy one I
either couldn't have one or it was outlandishly expensive. Guess
avalanching is the only game in town and if you want avalanche-rated
then a bone-simple BJT can easily shoot up to twenty bucks.
SRDs aren't hard to get. MA/Com has distributor parts, under a buck.
M-Pulse and Metelics are good about samples. If you want a few, send
me a SASE.

Oh, here it is...

229-1769 DIO SRD 30V SOT23 150PS MA44769 1PF

MA44769-287 PENSTOCK

Price 58 cents in small quantities.

They also have MA44767-287, 600 ps risetime, a little easier to drive
because it stores more charge.

These make nice edge generators and frequency multipliers. I have a
rubidium clock that generates the 6.3846826128 GHz frequency from a 10
MHz rock with an absurdly small number of cheap parts.

Thanks, John! That's a decent price. And thanks for the SASE offer, but
maybe I'll combine that with a beer at Zeitgeist when I get down there
Well, drop in. We have a zillion exotic parts in stock. And the
quality of Z's burgers has improved radically lately. Only biker bar I
know of with Chimay on tap.

As a kid I grew up in Europe and back then such exotic parts were very
hard to find over there, even at hamfests.
We were lucky. Tons of exotic surplus gear, lots of old teevees,
Allied and Lafayette and Fair Radio Sales mail-order available to
anyone, local distributors for over-the-counter transistors and
10-turn pots and such... the counter guys gave me more parts than I
ever paid for. I made a deal with my parents to dump my allowance in
favor of a revolving credit account with Allied, so I could just order
stuff. I made spending money fixing radios and TVs.

John

Still not as good as now. I just bought an excellent-condition HP 8568B
spectrum analyzer for $900. About 2 cents on the dollar. So far this
year I've bought test equipment that would have cost way over $100000
new, for probably $4k altogether. Amazing.

Cheers

Phil Hobbs
And I'm looking at, theoretically, a quarter million dollars worth of
sampling heads over there on my shelf. This is an amazing time to
start a niche business, or even an exotic hobby.

Is there anything available at reasonable cost that does zippy sampling
without needing a Goliath of a scope attached to it?

Not really. The 5000 and 7000 series scopes had sampling plugins - I
have a bunch, and they're dirt cheap now - but they were pretty bad
compared to the superb 11801-series stuff.


There is an 11802 on Ebay right now for $1k but untested, "powers up".
Thing is, I haven't gotten much more space here. A sampler for the 7704
over here would be nice. What is so bad with S-4 and 7S11? Ok, the
25psec risetime doesn't quite rival your gear but for most stuff that
should do.

That stuff works, but it's not as quantitative as the later gear. And
TDR is a fabulous thing to have, and the TDR on the 7-series stuff is
really mediocre.

Isn't this beautiful?

ftp://jjlarkin.lmi.net/Z250A.jpg
ftp://jjlarkin.lmi.net/Z250_TDR.jpg

(TDR of the test trace, J28 to J29)

There are some little USB samplers, but they're very expensive.


Probably not much of a market anymore and the TDR guys in the field
dont' need a precision under a foot to figure where they have to drop
the bucket of their Kubota.

Too much cheap surplus stuff on ebay, too. I'd love to do a cheapish
USB TDR, but there's probably no good market.

John

 

[John Larkin]

On Tue, 29 Sep 2009 13:29:48 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Jan Panteltje wrote:
On a sunny day (Tue, 29 Sep 2009 09:34:08 -0700) it happened Joerg
invalid@invalid.invalid> wrote in <7ier86F30e1vkU1@mid.individual.net>:

UJTs are cool.

Well, yeah, but you probably lived in the Netherlands as a kid. You guys
had dump handelaars and all sorts of electronics places. UJTs were
unobtanium in Germany. Once in a while we'd mount a car and head over
the border. But since I was a kid back then and didn't have my own car
I'd have to hitch a ride. We usually split the cost for gas and then it
was affordable for everyone, but you needed a whole day.

Later I lived in Zuid Limburg and with a stiff bicycle ride you could
haul stuff home from the surplus dealer in Margraten. Wrecked many
baggage racks that way, plus some chains, axles and so on. And found out
the hard way that bicycle brakes don't work so good with 50 pounds of
stuff on the back.

Still widely available, I used the 2N2646:
http://nl.farnell.com/unijunction-transistors-ujt

I like PUTs for things like laser interlocks. Unlike ICs, I know
exactly how they'll behave in fault conditions, which matters a lot.
Relays are good too.

Cheers

Phil Hobbs

I had a lot of fun with PUTs. They would drive TTL directly from that
upper gate thingie.

John

 

[John Larkin]

On Tue, 29 Sep 2009 16:01:55 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

On Sep 29, 6:37 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 29 Sep 2009 09:11:36 -0700 (PDT),Bill Sloman

bill.slo...@ieee.org> wrote:
On Sep 29, 2:40 am, dagmargoodb...@yahoo.com wrote:
On Sep 27, 6:37 pm,Bill Sloman<bill.slo...@ieee.org> wrote:

That's not auto calibration, that's just replacing trim pots and screw
drivers with digital pots and an eprom programmer.

Bill you're just being tedious.  Autocalibration is soooo 20th
century--we just don't feel the need to discuss it.  That doesn't mean
we don't do it.

You may do it as a matter of routine, although your personal database
doesn't show much sign of having been up-dated recently. John Larkin
doesn't seem to be entirely at home with the concept.

I'll do whatever works. Lately we've been moving entire nonlinear
channel calibration algorithms into FPGAs. But I'm not "entirely at
home" with building primary standards into measuring instruments, or
taking them offline for self-test or recal without an explicit command
from the user to do so. Even if I could do that transparently, my
customers *really* wouldn't like their gains an offsets being changed
invisibly, mid-run.

John Larkin does waste a lot of time constructing straw men. He makes
one of his typical exaggerated claims, I point that the claim isn't
valid if you put a primary standard inside the instrument, which is
possilbe, if not usual

http://tf.nist.gov/ofm/smallclock/CSAC.html

Is that in the Mouser catalog yet?

and he then proceeds to claim that I am advocating putting primary
standards in every instrument.

You've suggested it several times. Sounds like a developing
compulsion.

That's the problem having customers, I guess. It must be be very
liberating to have no customers.

Considering the amount of time you've spent building your straw man
and berating me for adopting a position that you took the trouble to
invent for me, it would seem that you must be running short on
customers at the moment, and are having to find other ways of filling
in your empy days. The anxiety seems to be making you irritable.

A day in the life:

Two customer-support calls

Five emails ditto

One customer inquiry about a new product, having to do with muons or
something

One meeting with the Xilinx folks, who I had to go fetch when they got
lost a few blocks away and couldn't find the place. That happens a
lot, actually.

Two neat part sample requests, both LC filters, Mini-Circuits and
Coilcraft.

One engineering meeting

About six mini-meetings, mostly technical

Lunch

One extended discussion about popular culture


I'm not irritable lately, but I can't design stuff with all that going
on. May as well kill time on the web between interruptions, looking at
news and checking the new product announcements and wiki-ing various
topics. I've got to get away to get anything real done these days.

I did get to design a pc board yesterday, a 24-channel high-voltage
ADC for a spectroscopy system, but that was routine part-plopping and
only took a couple of hours.

Some customers need certified data: confirm cal before a run, take
data, confirm cal after. The idea of continuous calibration is messy
there. The only things you might get away with would be tweaking
dimensionless things, like auto-zero or some such.

Our newer VME modules have a relay per channel and a test connector
(upper D9 in this case)

http://www.highlandtechnology.com/DSS/V450DS.html

so the customer can bus all the test connectors to a
tracable-calibrated DVM or whatever. He can pull in a relay and route
the channel to the cal instrument without disconnecting the field
wiring, making it a software-only thing to verify the cal of the
entire system, every morning if he wants. Why use relays? Because
Pratt&Whitney told us to use relays.

And you couldn't come up with a better alternative.

Actually, I couldn't.

John

 

[TralfamadoranJetPilot]

On Tue, 29 Sep 2009 08:33:04 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

nor is
going to shield your body potential from a field strength meter.

You are absolutely, 100% uneducated.

As well as being wrong.

 

[TralfamadoranJetPilot]

On Tue, 29 Sep 2009 08:33:04 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Waving arms in air builds up a charge on your body?

http://en.wikipedia.org/wiki/Triboelectric_effect

I think you just
enjoy waving your arms while wearing a cute smock.

Yes, it does, idiot. Your body collects ions from the air constantly,
and a lot is available...

When you do NOT have a smock on. When you DO have a smock on, you
still can attain a charge, it is just that you will no longer radiate
your field the same way as you would with a mostly insulative outer
surface over most of your body. With a conductive smock over most of
your body, your field gradient(s) is/(are) completely homogenized.

There are components which can be killed by field presence alone.

 

[TralfamadoranJetPilot]

On Tue, 29 Sep 2009 08:46:25 -0700, Rich Grise <richgrise@example.net>
wrote:

On Tue, 29 Sep 2009 05:48:56 -0700, TralfamadoranJetPilot wrote:

Case closed.

That means you'll be going away now, right?

Thank God!

The funny part about the crap you spew as 'something funny' is that it
is so old that it dates you completely... And it is such bad humor as
well.

God! How sad. You're an old, dead joke just standing there.

 

[T]

In article <23lsb5tf466bn2d72jnfognqporrtu7rsa@4ax.com>, To-Email-Use-
The-Envelope-Icon@My-Web-Site.com says...

Anyone with experience using Skype Video?

Is a dual-core processor really needed?

Camera recommendations?

...Jim Thompson

No it isn't needed. I have a Dell XPS M140 and I use it with a Sanyo
Xacti C40. I do need to run a video split program but other than that it
works just fine.

 

[Speeders & Drunk Drivers]

99 chevy malibu new motor 45k miles - Asking $25 Only (NewYork, NY)

--------------------------------------------------------------------------------
Date: 2009-09-27, 8:03PM PDT
Reply to: sale-264se-123395684388@craigslist.org [Errors when replying to ads?]

--------------------------------------------------------------------------------


so i have my extra car here and i don't need it since i bought an suv recently. its a 1999 chevy malibu. it has only one original owner. i bought it and haven't transfered it. i lost the title but i know the owner and they live in everett so i can go to them and have them sign a bill of sale to you and notarize it so you can go transfer it straight to your name without problems. i already did emissions and it passed without any problems. the tabs are expired. but still a great car. i have stuff listed below good and bad. theres only one thing wrong with this car and its listed below.

asking: 2500 or best offer. don't be shy to offer. i just need the money. can't work on it with a hurt back anymore.

trades are welcome but need the money more.

email: toyotaaqcosdolla2jz@yahoo.com

goods
new 2000 3.4liter impala engine with only 60,000k miles (i do have papers just gotta find it, has markings from the shop i bought it from)