Nice. And it refers to:
Thanks!John L, Jeorg: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
Read the whole thread. I can see how your approach will work.
Or use Gullah for proper comedic effect.On Sep 25, 1:47 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@My-
Web-Site.com> wrote:
On Fri, 25 Sep 2009 10:34:59 -0700, Jim Thompson
To-Email-Use-The-Envelope-I...@My-Web-Site.com> wrote:
Shades of the Hitler Youth Corps :-(
http://www.wnd.com/index.php?fa=PAGE.view&pageId=110898
...Jim Thompson
Suppose it was, instead...
Uhm, uhm, uhm, George W. Bush
He said all should lend a hand to make the country strong again
Uhm, uhm, uhm, George W. Bush
He said we must be fair today, equal work means equal pay
Uhm, uhm, uhm, George W. Bush
He said take a stand, make sure everyone gets a chance
Uhm, uhm, uhm, George W. Bush
He said red, yellow, black and white, all are equal in his sight
Uhm, uhm, uhm, George W. Bush
YEAH! George W. Bush
and taught in the schools during Bush's administration?
The leftist weenies would be apoplectic ;-)
What cretins!
...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 | |
| Voice
| E-mail Icon athttp://www.analog-innovations.com| 1962 |
LOSE the WUSS
BRING BACK BUSH
I'm sure the kids didn't make this up themselves.
It's probably some outcast figuring she can stir the shit pot with
this.
Or, it's lip-synching. Take your pick.
Then again, it might have had more credibility if someone ran those
lyrics through an ebonics filter before trying to pass them off as
Obama.
No way, they would have to use it as the blower for central HVAC for a
I ain't retired ;-)
480)460-2350 Fax: Available upon request | Brass Rat |Except you have the democrats and republicans mixed up.
I got it running before I went out of town. The setups let you set
480)460-2350 | |480)460-2142 | Brass Rat |What is this, just because he wants a little ROI on what he has paid
I can provide you one from the early '70s; it probably just bimetal
Yup. Used to provide about 5 V effective for the heavily damped dashOn Fri, 25 Sep 2009 19:32:15 -0800, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:
"langwadt@fonz.dk" wrote:
On 26 Sep., 00:33, Jim Thompson <To-Email-Use-The-Envelope-I...@My-Web-
Site.com> wrote:
On Fri, 25 Sep 2009 17:22:20 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
Jim Thompson wrote:
On Fri, 25 Sep 2009 16:06:57 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
My curious mind wants to learn the operating principle used in many
imported automobile turn signal flashers, the kind which increase their
flashing rate considerably when a turn signal bulb burns out. Their
flashing rate is inversely proportional to the load. That seems like a
good idea as it warns the driver that a bulb has gone s
outh.
I had some Ss & Gs last night helping youngest son fix the turn signals
on his 95 Honda so he could pass state motor vehicle inspection. The
right side turn signals, both front and back, were flashing way too fast
and rather dimly too.
The bulbs were the right spec and not burned out, so son soon reached
the limit of his expertise and sought my help.
The front turn signal bulbs were dual filament 1157s with the "bright"
filament used for the turn signal and the "dimmer" one for the marker light.
The problem turned out to be an open connection in the common (grounded)
lead to the front right bulb socket.
So, with the marker lamps off the load presented to the flasher from the
right front lamp socket was the two filaments of that bulb in series,
going to ground through the three paralleled marker lamp filaments on
the remaibning three corners of his car.
Fixing a corroded connection on the other end of the "bad" bulb socket's
ground lead cured the problem.
So, without my having to obtain and reverse engineer a flasher, what's
inside it that makes its flashing rate inversely proportional to load?
Thanks guys,
Jeff
Look up the part number and see what it is called. It might simply be
a bi-metal flasher. When you think automotive, think cheap ;-)
...Jim Thompson
That's why I posted the question here Jim.
I'm familiar with how the bimetalic flashers of yore were constructed,
but I couldn't think of an easy way to make a bimetalic flasher with a
flash rate inversely sensitive to the load placed on its output. (And
also let it deliver nearly full battery voltage to the bulbs.)
Thus, I figured it probably contains a solid state circuit
Jeff
I last did turn signal about 1968. BUT I do recall that bi-metal
flashers flash faster when one bulb was dead. I can't remember why
:-(
less current, less heat, quicker cool off ?
Two bi-metal strips, each carrying one contact of the flasher switch.
One is heated by a resistor to ground in parallel with the signal lamps.
The other is connected in series and heated by the lamp current. This
second strip moves when heated so as to increase the distance that the
first strip must move to make/break the lamp circuit.
Yup. I was vaguely remembering a heater to ground.
Anyone (besides me) remember the under-dash "voltage regulators" that
were bi-metal ?
...Jim Thompson
Yup. Good old 2n173 with autotransformer outputs.Jim Thompson wrote:
On Fri, 25 Sep 2009 19:32:15 -0800, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:
"langwadt@fonz.dk" wrote:
On 26 Sep., 00:33, Jim Thompson <To-Email-Use-The-Envelope-I...@My-Web-
Site.com> wrote:
On Fri, 25 Sep 2009 17:22:20 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
Jim Thompson wrote:
On Fri, 25 Sep 2009 16:06:57 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
My curious mind wants to learn the operating principle used in many
imported automobile turn signal flashers, the kind which increase their
flashing rate considerably when a turn signal bulb burns out. Their
flashing rate is inversely proportional to the load. That seems like a
good idea as it warns the driver that a bulb has gone s
outh.
I had some Ss & Gs last night helping youngest son fix the turn signals
on his 95 Honda so he could pass state motor vehicle inspection. The
right side turn signals, both front and back, were flashing way too fast
and rather dimly too.
The bulbs were the right spec and not burned out, so son soon reached
the limit of his expertise and sought my help.
The front turn signal bulbs were dual filament 1157s with the "bright"
filament used for the turn signal and the "dimmer" one for the marker light.
The problem turned out to be an open connection in the common (grounded)
lead to the front right bulb socket.
So, with the marker lamps off the load presented to the flasher from the
right front lamp socket was the two filaments of that bulb in series,
going to ground through the three paralleled marker lamp filaments on
the remaibning three corners of his car.
Fixing a corroded connection on the other end of the "bad" bulb socket's
ground lead cured the problem.
So, without my having to obtain and reverse engineer a flasher, what's
inside it that makes its flashing rate inversely proportional to load?
Thanks guys,
Jeff
Look up the part number and see what it is called. It might simply be
a bi-metal flasher. When you think automotive, think cheap ;-)
...Jim Thompson
That's why I posted the question here Jim.
I'm familiar with how the bimetalic flashers of yore were constructed,
but I couldn't think of an easy way to make a bimetalic flasher with a
flash rate inversely sensitive to the load placed on its output. (And
also let it deliver nearly full battery voltage to the bulbs.)
Thus, I figured it probably contains a solid state circuit
Jeff
I last did turn signal about 1968. BUT I do recall that bi-metal
flashers flash faster when one bulb was dead. I can't remember why
:-(
less current, less heat, quicker cool off ?
Two bi-metal strips, each carrying one contact of the flasher switch.
One is heated by a resistor to ground in parallel with the signal lamps.
The other is connected in series and heated by the lamp current. This
second strip moves when heated so as to increase the distance that the
first strip must move to make/break the lamp circuit.
Yup. I was vaguely remembering a heater to ground.
Anyone (besides me) remember the under-dash "voltage regulators" that
were bi-metal ?
...Jim Thompson
I don't recall those "regulators", but during my high school years I
worked for a radio shop is San Francisco and installed and repaired
plenty of car radios that used vibrator power supplies to create the B+
high voltage for the vacuum tubes.
Those vibrators dissapeared with the next generation of car radios which
used vacuum tubes requiring a plate voltage of only twelve volts, but
IIRC solid state audio output stages.
Jeff
Silly question.
Back when the Weston Standard Cell was the primary source for voltage,
I could do with being a bit less liberated. Even one customer would be
Using simple indexing to access really large data stores gets uglyOn Sat, 26 Sep 2009 12:17:04 -0400, jeff_wisnia
jwisniadumpthis@conversent.net> wrote:
Jim Thompson wrote:
On Sat, 26 Sep 2009 10:53:40 -0400, jeff_wisnia
jwisniadumpthis@conversent.net> wrote:
Jim Thompson wrote:
On Fri, 25 Sep 2009 19:32:15 -0800, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:
"langwadt@fonz.dk" wrote:
On 26 Sep., 00:33, Jim Thompson <To-Email-Use-The-Envelope-I...@My-Web-
Site.com> wrote:
On Fri, 25 Sep 2009 17:22:20 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
Jim Thompson wrote:
On Fri, 25 Sep 2009 16:06:57 -0400, jeff_wisnia
jwis...@dumpthisconversent.net> wrote:
My curious mind wants to learn the operating principle used in many
imported automobile turn signal flashers, the kind which increase their
flashing rate considerably when a turn signal bulb burns out. Their
flashing rate is inversely proportional to the load. That seems like a
good idea as it warns the driver that a bulb has gone s
outh.
I had some Ss & Gs last night helping youngest son fix the turn signals
on his 95 Honda so he could pass state motor vehicle inspection. The
right side turn signals, both front and back, were flashing way too fast
and rather dimly too.
The bulbs were the right spec and not burned out, so son soon reached
the limit of his expertise and sought my help.
The front turn signal bulbs were dual filament 1157s with the "bright"
filament used for the turn signal and the "dimmer" one for the marker light.
The problem turned out to be an open connection in the common (grounded)
lead to the front right bulb socket.
So, with the marker lamps off the load presented to the flasher from the
right front lamp socket was the two filaments of that bulb in series,
going to ground through the three paralleled marker lamp filaments on
the remaibning three corners of his car.
Fixing a corroded connection on the other end of the "bad" bulb socket's
ground lead cured the problem.
So, without my having to obtain and reverse engineer a flasher, what's
inside it that makes its flashing rate inversely proportional to load?
Thanks guys,
Jeff
Look up the part number and see what it is called. It might simply be
a bi-metal flasher. When you think automotive, think cheap ;-)
...Jim Thompson
That's why I posted the question here Jim.
I'm familiar with how the bimetalic flashers of yore were constructed,
but I couldn't think of an easy way to make a bimetalic flasher with a
flash rate inversely sensitive to the load placed on its output. (And
also let it deliver nearly full battery voltage to the bulbs.)
Thus, I figured it probably contains a solid state circuit
Jeff
I last did turn signal about 1968. BUT I do recall that bi-metal
flashers flash faster when one bulb was dead. I can't remember why
:-(
less current, less heat, quicker cool off ?
Two bi-metal strips, each carrying one contact of the flasher switch.
One is heated by a resistor to ground in parallel with the signal lamps.
The other is connected in series and heated by the lamp current. This
second strip moves when heated so as to increase the distance that the
first strip must move to make/break the lamp circuit.
Yup. I was vaguely remembering a heater to ground.
Anyone (besides me) remember the under-dash "voltage regulators" that
were bi-metal ?
...Jim Thompson
I don't recall those "regulators", but during my high school years I
worked for a radio shop is San Francisco and installed and repaired
plenty of car radios that used vibrator power supplies to create the B+
high voltage for the vacuum tubes.
My '50 Nash had a vibrator power supply and used the field coil of the
speaker as the choke.
And it was quite the battery killer when you "parked in the park"... I
always parked on a good downhill slope to ensure a rolling start ;-)
I had a 50 watt 10 meter ham rig in my '53 Willys Aero Ace back then.
I'd drive GFs up to the top of Twin Peaks in SF so we could see "how far
I could get." <G
I put a second car battery in the trunk wired in parallel with the car's
battery. to get enough engine off running time for the xmitter's
"dynamotor" B+ supply. Battery venting? "We don't need no stupid battery
venting."
What goes around comes around. My current set of wheels, a Lincoln LS,
has its battery located next to the spare tire, under the trunk floor.
Jeff
MIT guys are so creative.
I was scratching my head trying to remember what brand of radio was in
the Renault... my senior moment search engine finally just reported
back: "Automatic Radio" ;-)
...Jim Thompson
Since you are a such a prig there is no way you could treat a contact
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