Near disaster with PCB design...

In article <rakj3q$ku7$2@reader1.panix.com>,
Cydrome Leader <presence@MUNGEpanix.com> wrote:
John Larkin <jlarkin@highland_atwork_technology.com> wrote:
On Tue, 26 May 2020 10:34:47 -0700 (PDT), pcdhobbs@gmail.com wrote:

How do you keep track of who did what when, and especially why?

There are commit messages, tags, and several wonderful functions:

git diff
git whatchanged
git blame (who changed what when)
git cherrypick

How do you know *why* something changed?

How does diff or whatchanged apply to a schematic or a PCB?


And so on.

Multiple branches sounds hazardous to me.

You keep one master branch, owned by one person a la Linus Torvalds. (Git was written by and for the Linux kernel developers.)

Right. To manage text files.

What is a \"master branch\"? Sounds contradictory to me.

In the software biz, quality is achieved mostly by test, and it\'s OK
to finally get something right on the 12th try. PCBs are different.

We iterate PCBs carefully a step at a time, and ownership is
transferred formally. Same with manuals and such.

You\'re not missing out on anything if you have a process that works. git
can be complete clusterfuck when it goes south or you have merge conflicts
or something goes wonky between two branches people are working on.

It\'s a product so sophisticated it lacks something as simple a undo on a
step by step basis.
Click to expand...

The one fatal flaw of git is that the archives do not have a transparent
data format.
It is RCS/CVS any time for me. If the worst comes to the worst those
files can be fixed manually, or I can write scripts for them.
(I think RCS could be The Last Source Control if version 3.0 identified
the files with consequitive numbers instead of names, and multiple file
commits would be added.)

Groetjes Albert
--
This is the first day of the end of your life.
It may not kill you, but it does make your weaker.
If you can\'t beat them, too bad.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
 
In article <kk51dfpg98q450f7bfuhavjd85ovb165qh@4ax.com>,
<jlarkin@highlandsniptechnology.com> wrote:
On Thu, 28 May 2020 19:36:12 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Thursday, May 28, 2020 at 9:04:47 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Thu, 28 May 2020 17:44:16 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Thursday, May 28, 2020 at 6:39:01 PM UTC-4, John Larkin wrote:
On Thu, 28 May 2020 12:24:34 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Thursday, May 28, 2020 at 2:33:50 PM UTC-4, Piotr Wyderski wrote:
Ricketty C wrote:

If you don\'t want to futz with the LTspice simulation there is a PDF file of the schematic.

http://arius.com/temp/Current_Limit.pdf
\"My God, it\'s full of parts!\"

Why not a depletion-mode MOSFET with a resistor?

Best regards, Piotr

I don\'t think he can afford the ~1 V drop of the d-fet.
(I hear you responding that the above thing has a Vbe drop..
which I guess he can afford.) I\'m not sure about the
Schottky diode. Is that to reduce temperature effects?

George H.

The little LND150 Supertex parts get ohmic, around 1K, at low
voltages. The LED will get a bit dimmer at low supply voltage. The
not lethal.

I recently invented a cute LED current limiter, where the voltage drop
across the LED is the voltage reference for its own current. 4 parts,
8 cents, nearly zero headroom.

You\'d scribble it on the side here, but there\'s
not enough room in the margins :^)

Say, can you give us a hint? I bet \'we\' can figure it out.

George H.
(who will have to go look at the I-V curve of the lnd150 again.)


I\'ll draw it up and post it, but the thing I described devolves to a
negative resistor.
Huh.. OK.. I\'ve got a vague memory of a capacitor feedback circuit that
looked like a negative resistance. Does this gizmo oscillate?
(It\'s like \'What\'s my line\', Soupy Sales has the next question. :^)

George H.

This is it:

https://www.dropbox.com/s/awl6qmpax8ym8kl/CCLED_May_2020.JPG?raw=1

It only needs three parts, but negative resistors are perverse, so it
might not start up. So it needs R2A or R2B or something to kick it
off.

It only loses millivolts.
Click to expand...

I still have heaps of germanium transistors.
I\'m looking for uses for them, and this might be one of them.
For once the nice leakage current can be put to good use, such
that R2A can be missed. Moreover the saturation voltage is even
less.

--

John Larkin Highland Technology, Inc
Click to expand...

Groetjes Albert
--
This is the first day of the end of your life.
It may not kill you, but it does make your weaker.
If you can\'t beat them, too bad.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
 
On Friday, May 29, 2020 at 12:39:35 AM UTC-4, Cydrome Leader wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-05-27 16:45, Cydrome Leader wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-05-26 22:26, Cydrome Leader wrote:
John Larkin <jlarkin@highland_atwork_technology.com> wrote:
On Tue, 26 May 2020 10:34:47 -0700 (PDT), pcdhobbs@gmail.com wrote:

How do you keep track of who did what when, and especially why?

There are commit messages, tags, and several wonderful functions:

git diff
git whatchanged
git blame (who changed what when)
git cherrypick

How do you know *why* something changed?

How does diff or whatchanged apply to a schematic or a PCB?


And so on.

Multiple branches sounds hazardous to me.

You keep one master branch, owned by one person a la Linus Torvalds. (Git was written by and for the Linux kernel developers.)

Right. To manage text files.

What is a \"master branch\"? Sounds contradictory to me.

In the software biz, quality is achieved mostly by test, and it\'s OK
to finally get something right on the 12th try. PCBs are different.

We iterate PCBs carefully a step at a time, and ownership is
transferred formally. Same with manuals and such.

You\'re not missing out on anything if you have a process that works. git
can be complete clusterfuck when it goes south or you have merge conflicts
or something goes wonky between two branches people are working on.

It\'s a product so sophisticated it lacks something as simple a undo on a
step by step basis.


No, it doesn\'t. You can go back to any commit in the history with one
command.

Sure, if you want to throw all your work away. and give up any chance of
even a manual merge. Pretty clever feature.

You obviously don\'t know git well at all. Checking out an old commit
doesn\'t lose any information. You can also check it out into a new
branch, e.g.

It sounds like you only work with 3 other people with a small code base,
with infrequent changes if you haven\'t seen it fall apart yet.

git checkout -b backOne HEAD~1

which doesn\'t disturb the master branch even slightly.

Reverting a commit does throw stuff away, but normally it\'s only used to
fix extreme breakage.

Which isn\'t hard to trigger and not far in between.
Click to expand...

I used to manage version control software for a couple of teams. The software was not too hard to use and the concepts were straightforward. I tried using one of the open source VCS on my machine a few years ago and it was a disaster because the fundamentals were changed. Check in one file and they all get a new revision number! What is up with that??!!

The systems I used gave each file a separate revision history with incrementing numbers for each file. Then we could establish baselines with any files and any revisions we chose. It seems like tools like github want to do things very differently.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
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