Driver to drive?

[Rich Grise]

On Wed, 27 Oct 2004 13:32:55 -0600, uvcceet wrote:

To find such a useful, well stated explanation on a usenet group has to be a
giant stroke of good fortune, making it worth the trouble of wading through
the postings of all the political losers in the group.

Something that's also rare, and to be encouraged, the way I see it, is

folks who come back and not only acknowledge that there were answers,
but actually express gratitude for them. (how do you do a "good job"
smiley without getting it confused with a "haha just kidding" smilie?
'cause I'm not kidding.)

This is way cool, and is one of the inducements for the folks who answer
stuff to keep answering stuff. <- good smilie

Thanks for paying attention!

And thanks for the progress report!

Cheers!
Rich

 

[Rich Grise]

On Wed, 27 Oct 2004 14:58:20 +1000, Clifford Heath wrote:

Jonathan Kirwan wrote:
I'm thinking automated BJT tester, eh?

Why not make it three-way, with a uC driving them, and you have
a curve-tracer that can handle any type of 2 or 3 terminal device
in any orientation? I want one!

Hey, who don't want a three-way?!

>:->

 

[Jonathan Kirwan]

On 27 Oct 2004 06:15:24 -0700, Winfield Hill <Winfield_member@newsguy.com>
wrote:

Resistor R7 establishes a Q3 bias programming current. For good
control the designer can select R7 to swamp the opamp's Is supply
current. For example, if the opamp is an LF441 with Is = 0.15mA,
then R7 = 27k sets 1.25mA in R6 Q4 and establishes a 5mA standing
bias current in Q3. The additional current in Q1 also serves to
lower its emitter resistance (remember r_e = 25 ohms/Ie), which
may improve the opamp's performance.

Thanks. Got it and I think I understand most of it. I can develop the
reasoning for the equations you got, at least. (Approximately, as I think you
neglected a couple of diode drops in your Iq calc.)

The r_e, though, is 25.3mV/Ie at 25C (being the tangent slope of the exponential
curve at some Ie) and not "25 ohms/Ie" (where, I assume, you meant to imply Ie
expressed in mA)?

Anyway, looks good. By the way, should I want to add some offset so that the
Vin's range goes from 0V to 5V, instead of from -5V to +5V (for example), would
it be sufficient to simply inject some fixed current from the -15V Vs through a
resistor to the (-) input of the opamp (at virtual ground)?

Jon

 

[Joel Kolstad]

Joerg,

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:gVSfd.12223$6q2.1747@newssvr14.news.prodigy.com...

The problem with well insulated houses is the aluminum backed fiber wool
in outer walls. I could only get it going when hanging it on a wall
opposite of a large window facing east.

Interesting... I would think that -- unless the walls are grounded -- that
the WWVB 60kHz signal would go pretty much straight through without any
significant attenuation, due to the skin depth in aluminum at 60kHz being
far greater than the thickness of the wall insulation.

---Joel Kolstad

 

[Winfield Hill]

Jonathan Kirwan wrote...

The r_e, though, is 25.3mV/Ie ... and not "25 ohms/Ie"
(where, I assume, you meant to imply Ie expressed in mA)?

Exactly, think of Ie in mA and divide that into 25 ohms.
Mathematically it's 25-ohms * 1mA / Ie, but that's too hard
to remember. :&gt

Anyway, looks good. By the way, should I want to add some offset so that the
Vin's range goes from 0V to 5V, instead of from -5V to +5V (for example), would
it be sufficient to simply inject some fixed current from the -15V Vs through a
resistor to the (-) input of the opamp (at virtual ground)?

Yes, if you trust the 15V stability, natch.


--
Thanks,
- Win

(email: use hill_at_rowland-dotties-org for now)

 

[Jonathan Kirwan]

On Wed, 27 Oct 2004 14:58:20 +1000, Clifford Heath
<cjh-nospam@nospaManagesoft.com> wrote:

Why not make it three-way, with a uC driving them, and you have
a curve-tracer that can handle any type of 2 or 3 terminal device
in any orientation? I want one!

That's what I'm thinking. It *would* be nice to include the ability to slug out
very high current, short pulses for testing some of the fancy power
semiconductors, too, and at the same time the ability to delicately trickle out
precision .1uA currents through a small diode without oscillating -- speaking of
which, I need to simulate Win's latest with a simple diode on the output.

Jon

 

[Tam/WB2TT]

"Jon.boston" <jonspam@earthlink.net> wrote in message
news:55beeac5.0410251728.304ea24d@posting.google.com...

I'm looking for the best circuit to switch batteries from a parallel
arrangemnt to a series arrangement for stacking the voltage.

There are some high voltage (200V) and high current MOSFETs. Is this
the right approach? I'm looking for the series stack to be at
about 150V shen connected and 12V for each battery.

Can I switch both ends of the battery in and out of the circuit. I
would want to drive the MOSFET switches from a logic voltage, 5V =
Series, 0V= disconnected. Another set of FET switches would bring the
charge voltage over to the batteries.

Any pointers as to the best way to switch these batteries into the
stack and handle the large voltages would be appreciated.

I'm confused on how to drive the gates as they will each be 12V higher
than the next one.

Jon
You could set up a diode matrix, and for N batteries, N-1 NPN or NFET

transistors. Nice thing is that all transistors connect to ground.

Tam

 

[Rich Grise]

On Tue, 26 Oct 2004 20:29:05 -0700, Tom Seim wrote:

Rich Grise <rich@example.net> wrote in message news:<pan.2004.10.26.04.28.06.635978@example.net>...
On Mon, 25 Oct 2004 20:36:37 -0700, Tom Seim wrote:

You are covered because they have to pay for the contracts up front.
This is not a scam-it is for real. If you feel strongly that Kerry
will win then this is your opportunity to clean up.


The web site tells you how to sign up.

Well, we all might as well, because if Adolph^H^H^H^H^H^HGeorge wins,
American money will soon become valueless anyway.

Good Luck!
Rich

Sounds like another lib unwilling to put up REAL MONEY!!

I'm a liberal. You know I don't have anything that even _looks_ like
"real" money.

We just don't want the rich white guys to make it so we can't even get
drugs to escape from the horror and hopelessness of our slavery under
their hobnail jackboots.

Thanks,
Rich

 

[Joerg]

Hi Jim,

I wasn't using any exotic filtering... this design was for a consumer
product for Bowmar... they promptly went Chapter 11 owing me $6K. A
year later a lawyer called me and said the courts had ruled that
consultants were in the same legal status as employees, so I got all
the money, with interest.


I had a case like that, too, but was considered a business and not an

employee so I had to fight for it myself. But my contract said that it
would be my IP if not paid and I let the bankruptcy arbiter know that I
would exercise that right after a reasonable deadline. The company that
bought up the remnants needed my design so they paid up.

See Breadboard.jpg on the SED/Schematics page of my website. The
picture is of a 1/4 slice of the breadboard system I designed and used
to design ASICs before CAD.


Ah, the good old days. Great solder job. Did you cut off the top of the

board with a chain saw?

Aren't you in the Grass Valley / Nevada City area? I used to be up
there regularly when Silicon Systems was still active.


No, in Cameron Park which is on Hwy 50 between Sacramento and Lake

Tahoe. Grass Valley is not far away though. I think nowadays the main
activity up there is professional video gear and HDTV equipment. Not
much analog, mostly Virtex FPGA and stuff like that. They could benefit
if some cost reduction would be done but I guess it doesn't matter much
with these products. Until someone from Asia enters the market.

The signal here in Phoenix sucks... probably due to a lack of water
table.


Yes, and I believe it is similar north of Phoenix which doesn't help LF

signals in their travels either. We have Nevada in the path which is
partially bone dry as well but it doesn't seem to matter much. I still
think higher frequencies would help quite a bit.

The group that really needs to brush up on time sync are the TV guys. It
is no big deal to add a universal time signal plus time zone info in the
vertical blank period and then use it so that VCR clocks work right.
Some of that is done at least on the transmitter side but all the VCR
clocks I have seen still veer and go blink-blink after a power outage.

Regards, Joerg

http://www.analogconsultants.com

 

[Rich Grise]

On Tue, 26 Oct 2004 20:31:48 -0700, Tom Seim wrote:

I see you're still unemployed, fredfraud. Maybe Kerry can use somebody
skilled in illegal wiretaps!

Seim, did you know that if you had the emotional maturity of a
9-year-old, that you would be able to get the name of your current
scapegoat right?

Dupe.

 

[Rich Grise]

On Wed, 27 Oct 2004 08:12:54 -0700, Stonent wrote:

A coworker of mine is looking for a pcmcia card that can open and
close a circuit via software control. It has to be 16bit pcmcia
because the device he is interfacing it to only has pcmcia slots an no
other kind of slot.

Does something like this exists?

Have you checked with Google?

Good Luck!
Rich

 

[Rich Grise]

On Tue, 26 Oct 2004 22:33:21 -0700, TomH wrote:

Greetings,

I need to use a large number of banana sockets for a patchbay. Rather
than buying these by the hundred, I find that I can buy hard brass
tube of the correct internal diameter for a few cents. Now collegues
have told me that I must have these plated with nickel or similar to
get a good contact,

Your colleagues are idiots. Or maye their brother-in-law has a plating
shop.

Brass is superb for that kind of crap. It even solders good. And it
doesn't corrode much - ever seen a ship bell?

Have Fun!
Rich

 

[Rich Grise]

On Wed, 27 Oct 2004 09:22:21 -0700, Tim Wescott wrote:

Steve wrote:

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:f3gvn055muhogeh7q3vp2h4q9ij0b91opr@4ax.com...

On Wed, 27 Oct 2004 10:56:03 GMT, "Steve" <me@privacy.net> wrote:

What's wrong with letting screws show? Will that keep people from
buying it?

John



Afraid it might - since the front panel is only 4" x1", a couple of even
small screws will show up quite obviously. It's an audio consumer item for
putting alongside their expensive kit, and so it will help if it looks the
part too.

Steve


Then use black oxide coated stainless hex socket fasteners -- that
should be equally at home in an audio equipment rack or the engine bay
of a race car.

Button head.

 

[Rich Grise]

On Wed, 27 Oct 2004 01:33:46 +0000, Clarence wrote:

It seems there were none of the super explosives there when the 101st
took the place. So the stuff has been gone a long time.

Or has been a red herring all along.

Just because I know that George Bush and Dick Cheney are the reincarnation
of Vlad The Impaler doesn't mean I think Prince John is any better.

Vote Badnarik. Send a message.

Thanks,
Rich

 

[xray]

On 27 Oct 2004 14:54:23 GMT, Jim Yanik <jyanik@abuse.gov.> wrote:

Ever been hit in the face with a vegetable like you suggest? Think it
doesn't hurt?

No, actually. I guess you are speaking from personal experience? I can
only guess.

 

[Rich Grise]

On Tue, 26 Oct 2004 20:18:50 -0700, Tom Seim wrote:

Hell no. The "real" JFK was tough on defense and cut taxes. I admired
him and mourned his loss. If JFK showed up today with those ideals he
would be ridiculed by the likes of Dean, Kerry, and Edwards.

This is why I find it so incongrouous that you'd support the likes of
the Bush/Cheney/Rumsfield cabal. They're the ones that murdered Mr.
Kennedy, you know. This is quite widely known - he was snuffed by big
oil, which, "coincidentally," happens to be what all the murder is
about today. If they can't have it, then By "God", nobody will!

good Luck!
Rich

 

[Rich Grise]

On Tue, 26 Oct 2004 17:39:10 -0700, John Larkin wrote:

On Tue, 26 Oct 2004 19:32:00 GMT, Robert Monsen
rcsurname@comcast.net> wrote:


By the way, if your scroll down to the bottom of the link that mr Yanik
has posted, which attempts to corroborate the iraqi terrorist story, you
find an add for an Ann Coulter book "How to talk to a Liberal (if you
must)". Coulter, of course, deserves a pie in the face:


What a disgusting statement.

What? That that nazi apologist deserves a pie in the face?

Yes. Terribly disgusting.

The nazis deserve to feel the pain of every torture they have inflicted
since the beginning of time.

Pie in the face. Hah! Try death camp.

Thanks,
Rich

 

[John Larkin]

On Wed, 27 Oct 2004 21:50:58 GMT, Rich Grise <rich@example.net> wrote:

Button head.

Hey, just who are you calling a button head?

But seriously, the other cool kind are allen-drive cylindrical cap
heads recessed in in milled-out holes, black or stainless. Doesn't
work for sheet metal, of course.

John

 

[John Larkin]

On Wed, 27 Oct 2004 22:59:25 GMT, Rich Grise <rich@example.net> wrote:

When I'm elected president, I'm gonna have my inauguration in a big
stadium, and issue an assault weapon to everybody who shows up.

Sounds like a refreshingly short Presidency.

John

 

[Rich Grise]

On Wed, 27 Oct 2004 08:16:25 +0000, Robert Monsen wrote:

Aren't these funny?

Well, they would be, except for the corpses.

She is such a 'kick'. They were collected by Al
Franken in his book "Lies, and the Lying Liars Who Tell Them: A Fair and
Balanced Look at the Right". Thankfully, I didn't have to read her book.
He suffered through it for me. Thanks, Al, I owe you one.

Democracy is a compact of mutual respect: we agree before we speak and
vote to respect people's opinions and respect the outcome. Without
that, only force matters.

Yes, it's important to have respect for your opponents, like the respect
our dear Ann Coulter showed when writing those ugly, hateful opinions above.

I know, sticks and stones... but a pie is just a funny political
statement, and doesn't hurt anybody (except the dumb al-pieda throwers,
who are now facing felony pie throwing charges for soiling a $3,000
backdrop).

Al Pieda!

I LOVE It! Join The Al-Pieda and stop the nazi sarcophage!

Cheers!
Rich