Re: gEDA-user: BC547 vs. 2N3904
Does driving the transistor into cutoff but not saturation also count as saturation switching? CL No, saturation is when collector voltage drops below base level and the collector junction becomes forward biased. Charge stored in this junction is the cause of swithing delays. Swiching transistors have special doping that reduces carrier lifetime and speeds up the transistor. Transistors can be operated into cutoff on high frequency, this happens for example in B or C class RF amplifiers. Their parameters (hfe, fT) degrade a bit when the transistor approaches cutoff, so C class amplifiers cannot be operated on the frequences as high as in linear mode (class A) with higher DC current. But I think that this may be a problem above VHF band. Wojciech Kazubski ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
Thanks for the comment on refdes values. I'll add a few things to next year's notes for the students. It had never occurred to me to use anything but an upper case alpha character followed by a numeric value for a refdes, but students have a habit of trying the unexpected. It threw me for quite a while trying to understand what pcb was complaining about, since it referred to a CONN part which wasn't in either the schematic or the pcb netlist or the pcb file. Now I know about the lower case feature I'll know what to look for next time. Correct me if I'm wrong, but only lower case at the end of a refdes is ignored by pcb (but not by gsch2pcb), so something like Rp4 is ok. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Pointer to 3d CAD?
On Mon, Oct 30, 2006 at 11:27:59AM -0800, Dave N6NZ wrote: Off topic I know, but I need a pointer. Is there a decent FOSS 3D CAD program that will create STL files for simple parts? I don't know what a STL file is. FOSS 3D CAD is BRL-CAD which I use on Ronja: http://ronja.twibright.com/3d CL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
Stuart Brorson wrote: Note that you can't do this with things like CONNpower and CONNsignal. How do you renumber alpha refdeses? Admittedly, CONNpower and the like are easier to deal with than J1, J2, etc, but if you've got a board with thousands of components on it, then you can't give each a unique alpha refdes, and the above renumbering scheme is extremely convenient. Since we can't do backanno in gschem/PCB, this point is moot, however. We're pretty close to being able to do that. You can renumber automatically in PCB and it produces a file that with probably only a few minutes of perl hacking could be used to back annotate to gschem. Actually, I'll see if I have any energy left after halloween activities tonight to code up something. Since there is already a perl program for backannotating from pads all that has to change is the parser and that should be easy. -Dan ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
I am curious to know if your notes are available online, or are released under such a license that we can make them available to students here? I've put them on my web page ( http://www.durham.ac.uk/peter.baxendale ). They are pdfs but I can send you openoffice files if they are any use to you. They are just brief notes to support a simple assignment (4x2 hour sessions) so you may find them a bit basic. I'd be interested in hearing your own experiences using geda with students. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
On Tue, 2006-10-31 at 13:00 +, Peter Baxendale wrote: I am curious to know if your notes are available online, or are released under such a license that we can make them available to students here? I've put them on my web page ( http://www.durham.ac.uk/peter.baxendale ). They are pdfs but I can send you openoffice files if they are any use to you. They are just brief notes to support a simple assignment (4x2 hour sessions) so you may find them a bit basic. I'd be interested in hearing your own experiences using geda with students. Aha... I am a student myself actually (just starting a PhD), so have no direct experience with teaching gEDA. My own experience was that the learning curve is initially steep, but having got to grips with it, I find it far nicer than other EDA packages I've used. To keep things simpler, we try and provide symbols and footprints for all parts which students might be expected to use. We run a robot design project, subdivided into mechanical, electrical and software components. The electronics is done basically on strip board, but that is a sub-section on our PCB(s) with micro-controller interfaces ready to populate. I am one of the demonstrators for the electronics part of the lab, and the desire is (from the project's leader) that the students use gschem or similar to draw their schematics. We aren't yet at the stage where these students build custom PCBs, however various ideas for rapid prototyping (miniature milling setups) have been discussed as a future possibility. I'll show the notes to Dr. Long, who is in charge of the robot design project. The draw, simulate, layout exercise looks a lot like the sort of thing he was suggesting for more general ECAD teaching. Regards -- Peter Clifton Electrical Engineering Division, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA Tel: +44 (0)7729 980173 ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: Forwarding some gEDA teaching materials I've discovered:
On Tue, 2006-10-31 at 13:00 +, Peter Baxendale wrote: I am curious to know if your notes are available online, or are released under such a license that we can make them available to students here? I've put them on my web page ( http://www.durham.ac.uk/peter.baxendale ). They are pdfs but I can send you openoffice files if they are any use to you. They are just brief notes to support a simple assignment (4x2 hour sessions) so you may find them a bit basic. I'd be interested in hearing your own experiences using geda with students. Look under: http://www.dur.ac.uk/peter.baxendale/stuff/gEDA/ There is quite a nice simple little exercise there. Regards, -- Peter Clifton Electrical Engineering Division, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA Tel: +44 (0)7729 980173 ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
On 10/31/06, Peter Clifton [EMAIL PROTECTED] wrote: We run a robot design project, subdivided into mechanical, electrical and software components. The electronics is done basically on strip board, but that is a sub-section on our PCB(s) with micro-controller interfaces ready to populate. I am one of the demonstrators for the electronics part of the lab, and the desire is (from the project's leader) that the students use gschem or similar to draw their schematics. We aren't yet at the stage where these students build custom PCBs, however various ideas for rapid prototyping (miniature milling setups) have been discussed as a future possibility. Peter, When Dr. Long was at the Freedog meeting in August he gave out copies of an MDP DVD (Version 0.5.8 Beta). Is that DVD (or a more recent version) available for download? (* jcl *) -- http://www.luciani.org ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Forwarding some gEDA teaching materials I've discovered:
[whoops... managed to send to the list by accident!] Look under: http://www.dur.ac.uk/peter.baxendale/stuff/gEDA/ There is quite a nice simple little exercise there. Regards, ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: pcb refdes name restrictions?
Dan McMahill wrote: Stuart Brorson wrote: Note that you can't do this with things like CONNpower and CONNsignal. How do you renumber alpha refdeses? Admittedly, CONNpower and the like are easier to deal with than J1, J2, etc, but if you've got a board with thousands of components on it, then you can't give each a unique alpha refdes, and the above renumbering scheme is extremely convenient. Since we can't do backanno in gschem/PCB, this point is moot, however. We're pretty close to being able to do that. You can renumber automatically in PCB and it produces a file that with probably only a few minutes of perl hacking could be used to back annotate to gschem. Actually, I'll see if I have any energy left after halloween activities tonight to code up something. Since there is already a perl program for backannotating from pads all that has to change is the parser and that should be easy. ok, actually spent 10 minutes and cranked it out. gaf/utils/scripts/pcb_backannotate is in CVS. Any feedback would be appreciated. To use, *make a scratch copy of your design first*. Please don't mess up your active copy and blame me! If you use cvs or subversion or whatever, its a good time to check in your work first so you can undo all of these changes globally. open up your layout, run the pcb action :Renumber() and give a log file name. PCB will renumber your footprints and record its actions in the log file. Now run pcb_backannotate [--verbose] renumber_log_file pg1.sch [pg2.sch ...] and hopefully all of your changes will be back annotated. -Dan ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: experiences using geda with students
Peter Clifton wrote: We run a robot design project, . . . the desire is (from the project's leader) that the students use gschem or similar to draw their schematics. We aren't yet at the stage where these students build custom PCBs, however various ideas for rapid prototyping (miniature milling setups) have been discussed as a future possibility. I saw at one Univ. site, (maybe MIT) a lab procedure about using their owned spray etching station. I have tested a very environmentally friendly etchant using HCl and H2O2 and pure copper metal to start off a solution and it works well enough without spray, and precipitates copper hydroxide when pH neutralized leaving slightly salty water that can go down the drain. The copper hydroxide can be sent to the landfill or sold scrap even. This etchant recipe, originally published by Leo Van Loon, is easy to see through, easy to replenish by color change, and low risk of eating holes in clothes, and makes no stains on hands or clothes. Baking soda in water is all you need to neutralize/rinse just etched boards, and lye, (NaOH), and pH paper or meter is all you need to neutralize excess etchant. Replenishing is by adding HCl 35% and H202 35% -- it increases the volume of etchant, so you drain out some before replenishing the etchant. The chemicals are available and cheap -- $6/gal for acid, $13/liter for H2O2 35%, and those sizes are the right proportions to buy in to make the recipe. Here's a board etched with it: http://shop.cottagematic.com/elab/etched-board-epson-photo-paper.jpg This photo was out of focus, but it's easy to see in a bubble tank when laminate substrate is showing -- copper can still be seen on the bottom edge. http://shop.cottagematic.com/elab/etch-done.jpg With spray, it would be a more even etch over panels of boards, and easier to see the progress of the etch for first time success. When you make some standardizing assumptions like your board sizes are 90% 2x4 cm, 5% 3x6 cm, and none are longer than 6 inches; 95% of boards are single sided copper plus wire jumpers, surface mount only; the etch station is small and easy. The main thing to buy is an acid proof pump for the etch spray. If you have a fume hood to put it in, any old clear plastic or glass can be used for the low requirements of the tank size and strength, and assembled with silicone RTV like a fish tank. If you didn't have a fume hood, some kind of box with a slight vacuum fan to pull air through some baking soda would neutralize any HCl mist or vapor as it is done and purify the air inside the etch tank after the spray pump stops. the final thing required is a fish tank heater. That attaches to the lid so you can make a glass tube to lid wall seal with silicone RTV (again). I have all the parts and will be trying it out soon and report more on this list about it, and would negotiate to make you a system if there is no one who can budget time on it at your place -- It would be about $400 for a new pump, $100 for a used one and about 6 hours or less work to hire to get one assembled. John Griessen ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
I sent out a big bunch yesterday; people in the northeast US may get them tomorrow, else you'll start getting them next week. And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I'm waiting for a day when I'm less caffeinated. Regards, Mark [EMAIL PROTECTED] -- You think that it is a secret, but it never has been one. - fortune cookie ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Pointer to 3d CAD?
I have not tried it but if you look at http://ftp.brlcad.org/VolumeIV-Converting_Geometry.pdf it talks about STL file. STL Import and Export according to page 18. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: gwave installation failure on OpenBSD
guile-gtk-2.1-0.31 from http://geda.seul.org/sources.html fails on OpenBSD 3.9 with rm -f /usr/local/bin/build-guile-gtk rm -f /usr/local/bin/guile-gtk ln /usr/local/bin/build-guile-gtk-1.2 /usr/local/bin/build-guile-gtk /bin/sh ./mkinstalldirs /usr/local/lib /bin/sh ./libtool --mode=install /usr/bin/install -c libguilegtk-1.2.la /usr/local/lib/libguilegtk-1.2.la /usr/bin/install -c .libs/libguilegtk-1.2.so.0.0 /usr/local/lib/libguilegtk-1.2.so.0.0 install: .libs/libguilegtk-1.2.so.0.0: No such file or directory *** Error code 71 Stop in /home/clock/guile-gtk-1.2-0.31 (line 243 of Makefile). *** Error code 1 Stop in /home/clock/guile-gtk-1.2-0.31 (line 596 of Makefile). *** Error code 1 Stop in /home/clock/guile-gtk-1.2-0.31 (line 408 of Makefile). Does the gwave has to be based on something that is so nonportable that on OpenBSD 3.9 it cannot figure out path to it's own compilation result? CL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
Be very very afriad of those 01005 capacitors... They seem to be virtual quantum devices... either you know where they are or you don't. Seeing as they have very small mass the heisenberg uncertainty principle is working against you in that they are likely to soon be some where else. Steve M. On Tue, 2006-10-31 at 12:25 -0600, Mark Rages wrote: I sent out a big bunch yesterday; people in the northeast US may get them tomorrow, else you'll start getting them next week. And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I'm waiting for a day when I'm less caffeinated. Regards, Mark [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
On Tuesday 31 October 2006 13:25, Mark Rages wrote: And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I just opened my ten pack. Ten individual kits of parts and board, with ten instruction sheets, very nicely done. Perfect to inflict on several people at work. I'm waiting for a day when I'm less caffeinated. I'm going to give the first one to my Tech. He could do Brain Surgery if he wanted to do it. I'm going to get out my Stopwatch and see how fast he gets it done. :-) -- http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Time or order your SMD Challenge Board!
On 10/22/06, DJ Delorie [EMAIL PROTECTED] wrote: http://www.delorie.com/pcb/smd-challenge/ I just ordered 2. -- Samuel A. Falvo II ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
I suppose so... I ripped mine right open. The lands for the 01 05 's are verry teeny I'll maybe sharpen my soldering iron I need some fine solder wick. Shopping to do... John G Mark Rages wrote: And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
My tech got his together other then those 01005's which were apperently used to fill a couple of pico black holes. Steve M. Bob Paddock wrote: On Tuesday 31 October 2006 13:25, Mark Rages wrote: And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I just opened my ten pack. Ten individual kits of parts and board, with ten instruction sheets, very nicely done. Perfect to inflict on several people at work. I'm waiting for a day when I'm less caffeinated. I'm going to give the first one to my Tech. He could do Brain Surgery if he wanted to do it. I'm going to get out my Stopwatch and see how fast he gets it done. :-) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
I think I will drop into this group a brief passage fom Heisenberg's Quantum Theory translated into English in 1930. Dirac has set up a wave equation which is valid for one electron and is invarient under the Lorentian transformation. It fulfills all requirements of the quantum theory, and is able to give a good account of the phenomena of the spinning electron, which could previously only be treated by, ad hoc assumptions. The essential difficulty which arises with all relativistic quantum theories is not eliminated however. This arises from the relation 1/c^2 = u^2C^2 + p^2 in x + p^2 in y + p^2 in z between the energy and the momentum of a free electron. According to this equation there are two values of E which differ in sign associated with each set of P in z, P in y and P in Z. The classical theory could eliminate this by arbitrarily excluding the one sign, but this is not possible according to the principles og quantum theory. Here spontaneuos transitions may occure to the states of negative energy; as these have never been observed, the theory is certainly wrong. Under these conditions it is very remarkable that the positive energy-levels (at least in the case of one electron) coincide with those actually observed. So what was wrong? What occured that proved both theories were correct? Steve M. Steve Meier wrote: Be very very afriad of those 01005 capacitors... They seem to be virtual quantum devices... either you know where they are or you don't. Seeing as they have very small mass the heisenberg uncertainty principle is working against you in that they are likely to soon be some where else. Steve M. On Tue, 2006-10-31 at 12:25 -0600, Mark Rages wrote: I sent out a big bunch yesterday; people in the northeast US may get them tomorrow, else you'll start getting them next week. And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I'm waiting for a day when I'm less caffeinated. Regards, Mark [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: smd challenge board status
I think I will drop into this group a brief passage fom Heisenberg's Quantum Theory translated into English in 1930. Dirac has set up a wave equation which is valid for one electron and is invarient under the Lorentian transformation. It fulfills all requirements of the quantum theory, and is able to give a good account of the phenomena of the spinning electron, which could previously only be treated by, ad hoc assumptions. The essential difficulty which arises with all relativistic quantum theories is not eliminated however. This arises from the relation E^2/c2 = u^2*C2 + p2 in x + p2 in y + p2 in z between the energy and the momentum of a free electron. According to this equation there are two values of E which differ in sign associated with each set of P in z, P in y and P in Z. The classical theory could eliminate this by arbitrarily excluding the one sign, but this is not possible according to the principles og quantum theory. Here spontaneuos transitions may occure to the states of negative energy; as these have never been observed, the theory is certainly wrong. Under these conditions it is very remarkable that the positive energy-levels (at least in the case of one electron) coincide with those actually observed. So what was wrong? What occured that proved both theories were correct? Steve M. Steve Meier wrote: Be very very afriad of those 01005 capacitors... They seem to be virtual quantum devices... either you know where they are or you don't. Seeing as they have very small mass the heisenberg uncertainty principle is working against you in that they are likely to soon be some where else. Steve M. On Tue, 2006-10-31 at 12:25 -0600, Mark Rages wrote: I sent out a big bunch yesterday; people in the northeast US may get them tomorrow, else you'll start getting them next week. And I'm interested in hearing your initial reactions, as well as any success stories :-) Am I the only one afraid to open the envelope? It just sits on my workbench, mocking me. I'm waiting for a day when I'm less caffeinated. Regards, Mark [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
