Marriage is under fire!!

[Tim Auton]

bullmordt@yahoo.co.nz (G.K. Konnig) wrote:

I like sex with myself and now I decided to build a robot clone of myself.

What do I need ?

You'll probably have to look around a lot for a 2-bit microprocessor.
How you will perform the divide-by-two on your wit will depend on the
width of your bus.


Tim
--
Guns Don’t Kill People, Rappers Do.

 

[NO SPAM]

"G.K. Konnig" <bullmordt@yahoo.co.nz> wrote in message
news:3ff97a0d.0409131058.37bd7429@posting.google.com...

I like sex with myself and now I decided to build a robot clone of myself.

What do I need ?

Now THERE is one for the books!

NS

 

[John Larkin]

On 13 Sep 2004 11:58:01 -0700, bullmordt@yahoo.co.nz (G.K. Konnig)
wrote:

I like sex with myself and now I decided to build a robot clone of myself.

What do I need ?

Psychotherapy, for starters.

John

 

[Gene the Skeptic]

What kind of "feedback" are you using? If it is just resistive it is
unlikely that the circuit becomes unstable because there is only one pole,
created by the OPAMP transfer function characteristics (-6dB/oct slope) and
the resistor in the feedback.
Gene

 

[Alessandro Mulloni]

Terry Pinnell wrote:

Alessandro Mulloni <mullah@dontspam.loyalmail.co.uk> wrote:


Hi everyone,

I must state first that I'm a total beginner in electronics.

I have a problem with a simple Ni-Cd battery recharger circuit. The
diagram is the sequent

---------------------- 1N4004 diode
+ o----|----------|input (LM317) output|----|----------->|----o +
| | adj | > U
input | ---------------------- > 47ohm U
= 0.1uF | | battery
| |---------------- U
- o----|--------------------|---------------------------------o -

and the input is between 4V and 12V DC.

What I would like to get is 1.25V between the adj and output pins (as
should be from the LM317 specs)

What I get is a varying voltage depending on the input one (that is,
3.3V if the input is 4V, 4.8V if the input is 5.5V, and so on..)

Do you all know why this is possible? Shouldn't the LM317 in the above
circuit guarantee 1.25V _always_ between the adj and the output pins?

Thank you all in advance.


There are some aspects of your schematic that I'm unclear about. Is
the lower end of your 47R connected direct to ground, as apparently
drawn? Or to the wiper of a pot, as would be the case for variable
control? If the latter, what is its value? And, although not strictly
relevant to your question, what voltage battery are you charging?

Anyway, begging answers to those, here are a couple of simulations
that may help.

http://www.terrypin.dial.pipex.com/Images/317Source.gif

Nice diagrams, thanks the lower pin is connected directly to the
ground, like in your first diagram.

My circuit is indeed _exactly_ the one drawn in your first diagram,
except from the voltage I get.

The battery is a 1.2V AA or AAA. With the 47R I would like to get some
27mA load so I can recharge even the 250mAh batteries, maybe I'll change
the resistor when I'll realize I only have batteries with more mA so to
recharge them in a shorter time. Without a constant voltage between the
output and the adj pins I cannot precisely do this calculation (that's
simply I = V / R).

Alessandro

 

[Alessandro Mulloni]

Byron A Jeff wrote:

In article <fZi1d.311794$5D1.13772702@news4.tin.it>,
Alessandro Mulloni <mullah@dontspam.loyalmail.co.uk> wrote:
-Hi everyone,
-
-I must state first that I'm a total beginner in electronics.

Well congratulations.

-
-I have a problem with a simple Ni-Cd battery recharger circuit. The
-diagram is the sequent
-
- ---------------------- 1N4004 diode
- + o----|----------|input (LM317) output|----|----------->|----o +
- | | adj | > U
-input | ---------------------- > 47ohm U
- = 0.1uF | | battery
- | |---------------- U
- - o----|--------------------|---------------------------------o -
-
-and the input is between 4V and 12V DC.

Looks like a standard constant current LM317 charger circuit.

-
-What I would like to get is 1.25V between the adj and output pins (as
-should be from the LM317 specs)

Not exactly. NiCads want constant current and are not too concerened about
the voltage requirements. Hence the single 47 ohm resistor which will for
a constant 1.25V/47 Ohm -> 26 mA of current across the battery.

Yes, I need 1/10 of the mAh of the battery to recharge it, but with a
non-constant voltage between the output and adj pins how can I calculate
properly the value of the resistor (currently set to 47ohm)?

-
-What I get is a varying voltage depending on the input one (that is,
-3.3V if the input is 4V, 4.8V if the input is 5.5V, and so on..)

That's exactly how it's supposed to work. Measure the current. You'll find that
the current stays the same even as the voltage fluctuates.
-

-Do you all know why this is possible? Shouldn't the LM317 in the above
-circuit guarantee 1.25V _always_ between the adj and the output pins?
-

Nope. The current is fixed, not the voltage.

Ok, but what I really do not understand is that by specifications the
LM317 should guarantee 1.25 of voltage between those pins. Is there
maybe some wrong connection in my circuit?

Alessandro

 

[Peter Bennett]

On 13 Sep 2004 14:51:03 -0700, smpaladin@yahoo.com (smpaladin) wrote:

Peter Bennett <peterbb@somewhere.invalid> wrote in message news:<p4t9k0lg3sb1nvnhq56l9ulpj67agr3odd@news.supernews.com>...
Now is there any kind of switch that will reverse the polarity of the
coil electrically like in this picture?
http://www.geocities.com/smpaladin/switch.jpg

Once a current is applied to the red switch, it reverses the polarity
of the coil as long as the current is applied. If this sounds
ridiculous, don't blame me since I may have no idea what I'm talking
about.


The "red switch" would be a double pole, double throw relay, with its
contacts wired as shown above (but you'd probably also want another
switch to turn the coil off...)

Could you refer me to more specific information about a double pole,
double throw relay? Thanks.

See
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=255055&Row=258133&Site=US
or search http://wwwdigikey.com for "dpdt relay"




--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[Chaos Master]

bullmordt@yahoo.co.nz, code name G.K. Konnig , on 13 Sep 2004 11:58:01 -0700 to
sci.electronics.basics in the article
<3ff97a0d.0409131058.37bd7429@posting.google.com>:

I like sex with myself and now I decided to build a robot clone of myself.

What do I need ?

High voltage. VERY high voltage. Kills trolls in a moment.

[]s
--
Chaos MasterŽ, posting from Brazil. REPLY TO GROUP!
"People told me I can't dress like a fairy.
I say, I'm in a rock band and I can do what the hell I want!"
-- Amy Lee

Note: this e-mail address goes to /dev/null.

 

[Tim Wescott]

Steven O. wrote:

Hi, all. I'm a tech writer, and recently decided to learn more about
electronics. Along the way I've picked up four or five textbooks,
most of which came with various software -- some student versions,
some trial versions, etc.

I finally signed up for an actual course on introductory Digital
Design, and we are using a book Digital Design by Morris Mano. The
book comes with software from SynaptiCAD, but most of the stuff only
runs in seriously crippled mode (no Saving, for instance); you can
get a 30-day trial license, but after that you have to pay huge sums
of money to run the software. (I went to their Web site, and could
not find personal or student versions for most of this stuff, with one
exception

It does come with one "lite" version that seems to be operational, a
program called WaveFormer Lite. (The other, cripple-ware programs are
called VeriLogger Pro, Timing Diagrammer Pro, and DataSheet Pro.)

Now -- and I'm working my way up to my question -- the professor
already told us that we don't need to use any of the software for the
class. (And, apparently, he plans to offer no instruction on how to
use the software.) But it seems to me it might help me to use some
CAD software, both to better understand the material, and to work more
effectively with the EEs that I deal with on the job (which is the
real, main goal of this exercise).

So, the question is, of all the various software I've accumulated,
which of this stuff should I try to learn? There's a lot of software,
and I have no idea which of it is really applicable for my current
needs. The criteria, at least for now, are:

1. Is relevant for learning the basics of digital design. (Some
major chapters in the book: Combinational Logic, Synchronous
Sequential Logic, Registers and Counters, Memory and Programmable
Logic, Register Transfer Level, Asynchronous Sequential Logic). The
back cover indicates that the book uses Verilog HDL.

2. The software can be a limited, student version -- perhaps it won't
let me build a commercial-scale application -- but it has to let me
build applications large enough for typical student purposes, and to
save them.

3. If the trial version expires after 30 days, the student edition
(or something similar) is cheap cheap cheap. I don't have thousands
of dollars to spend on this stuff.

As I say, I have a bunch of stuff sitting here, and I'm not even
entirely sure which of it is trial software and which isn't -- I don't
want to install all this stuff, without knowing which items I really
need. Anyway, the criteria are listed above. The options are:

(A) The WaveFormer Lite, that came with the book.
(B) A whole slew of programs from XiLinx that came with another book.
The programs include: Project Navigator, Chip Viewer, Constraints
Editor, CORE Generator System, Design Manager, Floorplanner, FPGA
Editor, HDL Bencher, iMPACT, LogiBLOX, PROM File Formatter, StateCAD,
Timing Analyzer, XPower. This all sounds like ASIC and FPGA design
stuff to me, rather than basic Verilog HDL stuff, but I could be
wrong.
(C) I have a CD called Electronics Workbench/MultiSim that came with
one of the textbooks I purchased.
(D) I have another CD called Schematic Capture Using MicroSim PSpice,
that came with another textbook. For both (C) and (D), I have no idea
if these are trial versions, or cripple-ware, or what.
(E) Finally, with a book called Fundamentals Of Electronic Circuits,
the included CD has software called MultiSim 2001 Textbook Edition.
(Which may be the same stuff as on the CD listed in (C) above.

So, can anyone -- perhaps a student or teacher who has worked with
these CDs, and this software -- tell me both which of this software is
relevant for my current studies; and which also either comes in
adequately functional form on the CDs that came with the book (like, I
can Save the files I create), or can be purchased (at least at the
student level) at very, very modest prices?

Also, if there is yet another option I've missed -- perhaps some Open
Source tool -- please let me know.

While you are at it, and if you really have time to burn, you might
let me know -- for future reference -- what some of these other
programs are for, even if not relevant for my immediate needs.

Thanks in advance for all replies.

Steve O.


"Spying On The College Of Your Choice" -- How to pick the college that is the Best Match for a high school student's needs.
www.SpyingOnTheCollegeOfYourChoice.com

The Xilinx tools are good, they're a whole design suite. I'd download
the latest copy from Xilinx's website -- you'll also get a copy of
Modelsim, which you can use for doing simulations on your computer.

Linear Technology has LT spice available for free from their website.
I've only used it a bit, but it seems to be very good (better for what I
do than anything else I've used). They're using it to sell their chips,
of course, so the libraries are light on other parts.

But in the end I agree with your professor. You want to learn the
theory, not the tools. If you feel a need to get anything, get a
protoboard kit from rat shack and some 74HCxx logic and do some hands-on
work. That'll get you way more than software tools.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Ban]

FS wrote:

When employing an op amp in a negative feedback configuration, phase
shifts due to the feedback loop, and the op amp itself can lead to
oscillation. I am experiencing something like this with the 741. Of
course I can play some tricks with capacitors, but my first question
is: Where can I find a simple resource describing the differential
equation for this scenario? Perhaps I have overlooked one on the web,
or maybe a good textbook will do (Horowitz and the Jung "Cookbook"
didnt'help here)

Thanks for any tips
Fritz

Google for "opamp stability criterion" or similar. You can do that by
analyzing the actual circuit inside the opamp together with stray
capacitances from the PCB layout, or by the bode-plot resulting from it.
Whenever the open loop gain is greater than 1 *and* the phase-shift gets
180°, the amp will oscillate.
When you use reactive compensation elements, these are not dirty tricks, but
scientifically chosen components which tailor the transfer function in such
a way to insure stability.
--
ciao Ban
Bordighera, Italy

 

[Ban]

Alessandro Mulloni wrote:

The battery is a 1.2V AA or AAA. With the 47R I would like to get some
27mA load so I can recharge even the 250mAh batteries, maybe I'll
change the resistor when I'll realize I only have batteries with more
mA so to recharge them in a shorter time. Without a constant voltage
between the output and the adj pins I cannot precisely do this
calculation (that's simply I = V / R).

Alessandro

http://www.national.com/ds.cgi/LM/LM117.pdf page 17 precision current
limiter,
look your schema is wrong, there is no connection to gnd, just inserted into
the 12V line. Also the rsistor has to be in series with the load and the
adj. pin is connected at the load side.
--
ciao Ban
Bordighera, Italy

 

[Terry Pinnell]

"Keith" <user@host.com> wrote:

Looking for suggestions on what to use for doing up some pcb layouts.
I am doing up some simple circuits for guitar effects and amplifiers. I
would like something that is not too complex.
Hoping for something that is free, but has support for printing. (going to
try the laser printer / photo paper trick)
I have tried ExpressPCB, and i liked it, but the copper trace printouts have
dots all over them (am i doing something wrong?)
Suggestions are appreciated. Thanks

See my notes and links to some 60 ECAD programs at
http://www.terrypin.dial.pipex.com/ECADList.html

Terry Pinnell
Hobbyist, West Sussex, UK

 

[Alessandro Mulloni]

Peter Bennett wrote:

In that case, I suspect that you have the 317 connected incorrectly.

See http://vancouver-webpages.com/peter/lm317.gif for the correct
pinout for a TO-220 package. That drawing shows a fixed-voltage
regulator. For the fixed-current regulator that you want, the Adjust
pin should not be grounded, and the output is taken from the junction
of the adjust pin and the resistor.

CFoley1064 wrote:

Hi, Alex. Are you sure you've got the pinout on the IC right? It's different
than the LM78XX. This shows the TO-220 IC as viewed from the front of the
package (view in fixed font or M$ Notepad):

LM317 Front View
.---------.
| o |
| |
|---------|
| |
| |
| |
| |
| |
'---------'
| | |
| | |
| | |
| | |
ADJ OUT IN

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

One of the famous newbie problems with the LM317 -- check your wiring and
pinout. I did it myself once many years back.

Good luck
Chris

Ban wrote:

http://www.national.com/ds.cgi/LM/LM117.pdf page 17 precision current
limiter,
look your schema is wrong, there is no connection to gnd, just
inserted into
the 12V line. Also the rsistor has to be in series with the load and the
adj. pin is connected at the load side.

Thanks for all your replies.

The problem was not in the pinout, but in the circuit itself. I actually
got it right at the first time (that is the Ban's circuit), but it
wasn't working, so I changed it to the one posted to this newsgroup.

When I went back to the original circuit, I noticed that something was
wrong.. I didn't have 12V in input, but -12V I know it's a stupid
mistake but I didn't even had a tester the first time I made the circuit.

Anyway, the problem is gone, the input + and - are connected in the
right way into the circuit, and I have some nice 1.25V between the
output and the adj pins.

Thanks everyone.
Alessandro

 

[Steven O.]

Mano is probably the most widely used textbook at the introductory
level. Use the *simplified* cripple-ware that came with the book to work
the exercises and it will be good enough. Anything more specialized will

Okay, fair enough. But again, I want to focus my time effectively.
Of the various programs that came with the book, is there just one
that primarily would relate to the content? The options are
WaveFormer, VeriLogger, Timing Diagrammer, and DataSheet. In other
words, which one should I try to learn, or at least learn first?

Also, did Synapticad ever sell student versions of these programs,
perhaps in earlier releases, and if so, are they available someplace
for sale? Again, it would be nice to save files I create for
practise.

Most competent people work through the entirety of Mano in a
week's time anyway.

Well, this is a community college class, so we're taking it a bit
slower....

Thanks again.

Steve O.

On Tue, 14 Sep 2004 14:28:55 GMT, Fred Bloggs <nospam@nospam.com>
wrote:

Steven O. wrote:
Hi, all. I'm a tech writer, and recently decided to learn more about
electronics. Along the way I've picked up four or five textbooks,
most of which came with various software -- some student versions,
some trial versions, etc.

I finally signed up for an actual course on introductory Digital
Design, and we are using a book Digital Design by Morris Mano. The
book comes with software from SynaptiCAD, but most of the stuff only
runs in seriously crippled mode (no Saving, for instance);

Mano is probably the most widely used textbook at the introductory
level. Use the *simplified* cripple-ware that came with the book to work
the exercises and it will be good enough. Anything more specialized will
require that you spend more time struggling with bug-ridden and complex
CAD than with the essential course material itself- and that would be
STUPID. Most competent people work through the entirety of Mano in a
week's time anyway.

"Spying On The College Of Your Choice" -- How to pick the college that is the Best Match for a high school student's needs.
www.SpyingOnTheCollegeOfYourChoice.com

 

[Gene the Skeptic]

Hi Fritz,

the discipline that studies this topic is called "Control Theory" and it is
quite complex. A book I could recommend is "Automatic Control Engineering"
by Francis Raven. In any case, a loop that is unstable( oscillations) is
indicative of excessive phase lag and gain above unity. I do not know if you
have the capability to perform an open-loop Bode-plot, but if you were it
would tell you the degree of instability of the loop and the way to
stabilize it. Adding capacitors will not solve the problem. Considering your
lack of knowledge in this field I recommend the following:
1. Reduce the gain of the OPAMP until the loop has good stability.
2. Is the performance accettable? if yes, leave it. If not go to the next.
3. Is there a tracking error problem? If yes you could try to to put a
capacitor in SERIES with the feedback resistor that sets the OPAMP gain.
Start with a big one and step by step decrease its value until the loop
become unstable. Mark the capacitor value when this happens. Intall a cap
that has double of the capacitance. Now the loop should be stable, with
virtually zero tracking error.
4. If you have dynamic tracking problem, then it is problematic to improve
the situation without having control theory knowledge.

Das Glueck ist dem Kuehnen hold!

Gene

 

[Dana Raymond]

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:2qp2i01batnet05aj41o037ggdq2ogdh85@4ax.com...

On Mon, 16 Aug 2004 17:18:37 -0700, "Fritz Oppliger"
fritzo_two_@direcway.com> wrote:


I came across a new one today:
eprom (27c512) programs fine,
verifies fine,
runs like crap. lots of errors.
Same code in an emulator runs fine.
Same code read back into the programmer and verified again fine.
Same code in another physical 27c512 chip runs fine (same target board).
What could the chip be doing differently when plugged into the target
board vs. the programmer?

Could be slow access time.

John

Another possibility is that the part has been stressed with ESD or some
other operating condition. EPROM programmers do not run the part at full
speed so it may pass in the programmer and fail in the target. It sounds
like we're talking about a single EEPROM here - chuck it out!

 

[Gene the Skeptic]

I agree 100%. The theory can lead to the "ballpark", but then good lab
investigation and analysis finalizes the design.
Gene

 

[Ban]

FS wrote:

Thanks for your reply Ban-
as I mentioned I am trying to analytically calculate the oscillation
rather than resort to "tricks" or trial-and-error here. I did not find
anything on the web which describes negative feedback in terms of a
second order differential equation however I presume the electronics
terminlogy here is "transfer function" and maybe I am looking to much
at the mathematical approach to this kind of problem. I will head out
to the library and see what I can find on feedback loops.

Thanks
Fritz

Fritz, the EEs do not use differential equations for their transfer
functions, but the Laplace transforms with the frequency operator S= j
f/f_nominal. This way the whole thing can be solved with simple algebra and
can be overlooked easily.
--
ciao Ban
Bordighera, Italy

 

[john jardine]

"Ban" <bansuri@web.de> wrote in message
news:qgw1d.249435$OR2.11281411@news3.tin.it...

Whenever the open loop gain is greater than 1 *and* the phase-shift gets
180°, the amp will oscillate.
When you use reactive compensation elements, these are not dirty tricks,
but
scientifically chosen components which tailor the transfer function in
such
a way to insure stability.
--
ciao Ban
Bordighera, Italy


I don't know about the rest of the world out there, but before spice

simulators, I never ever found a circuit that could be nicely stabilised by
the application of cold theoretical methods.
Disregarding of course, those trivial textbook examples, or the cop-out of
slugging the response to that of treacle, or having available a roomfull of
gain/phase measuring equipment, or having a pocketfull of those nice,
dominant poles that everyone except me seems to have in their toolkit.
The impossible to define parasitics seem always a major factor. The
semiconductor data sheets give too little info. The source and load Z's are
usually nothing like those estimated.
That 20nH of unseen, inductive cross-coupling may be impossible to analyse,
measure, estimate, simulate or (sometimes) even understand but is resulting
in 200megs oscillation, massive current drain and signal distortions, random
device failures and exciting artefacts in the preceding electronics.
Any solution must come from an in-the-flesh-on-the-bench-suck-it-and-see
approach. With experience it gets easier to home in on the sweet spots but
it's still ad-hoc and unscientific.

As the best *fixes* usually seem to involve the odd strategic R or C (or
god forbid, an occasional L), to me it still most definitely feels as if I'm
cheating or playing a dirty trick on the circuit, when just by adding that
critical 2p cap' the response instantly changes from a monstrous nightmare,
to that of pure sweetness and light.

Unless others know better

regards
john

 

[Jamie]

nice way of getting low cost design work done :/


Benny wrote:

Objective: The purpose of the Electronic Design Contest is to promote
excellence in the design of electronic systems and help the company to
improve circuit design quality by providing competition between
graduate and undergraduate students at universities and colleges.

Award: The 1st winner will be grant $100, and the 2nd winner will be
grant 10% discount coupon.

Problem: Design DC. motor speed control circuit that is used to
control the speed of direct current. Click here for more information
(Please don't copy the design from a link.)

Criteria: Submissions are made electronically via the TechnologyKit.us
web site. Electronic Design Diagram must be drawn in Microsoft Visio
file format. The deadline for submission is October 30, 2004

Check out on www.TechnologyKit.us for more information.