Help on circuit layout

[Chris]

I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

 

[Graham Knott]

Chris wrote:

I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

No

Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

 

[Clarence]

"Graham Knott" <g.knott@ntlworld.com> wrote in message
newsObjd.2147$QO4.768@newsfe1-gui.ntli.net...

<snip>

Oh dear,another troll.
I always give my best regards to trolls hoping that it makes their life
just a little bit happier.
Best regards Clarence.
--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

No, I'm not, but I know one when I encounter one!

You seem to have a problem relating to people.

 

[Jonathan Kirwan]

On Sat, 06 Nov 2004 21:58:44 GMT, "Graham Knott" <g.knott@ntlworld.com> wrote:

Oh dear,another troll.
I always give my best regards to trolls hoping that it makes their life
just a little bit happier.

I've long since permanently killfiled him. When I get to read him quoted by
others, though, I continue to see the sharp wisdom of that decision.

Jon

 

[David Harmon]

On Sat, 6 Nov 2004 17:26:21 -0600 in sci.electronics.basics, "James T.
White" <SPAMjtwhiteGUARD@SPAMhal-pcGUARD.org> wrote,

Some observations:

1) Your schematic and board don't seem to match. For example there are 6
diodes on the board and only 4 on the schematic. Also, the input power
connector seems to have all three pins connected on the board and only 2
connected on the schematic.

This strikes me as very odd. In my experience, that's the sort of thing
Eagle gets right 100% of the time. You draw the schematic, then tell
Eagle to "create board from schematic". It gives you a created board
file with all the parts, and airwires for all the net-connections.
However you proceed to move the parts around and route the connections,
the airwires don't go away until you are done.

 

[Clarence]

"Jonathan Kirwan" <jkirwan@easystreet.com> wrote in message
news:gmoqo0d2p41q38snvqdcnvsevidisktvlt@4ax.com...

On Sat, 06 Nov 2004 21:58:44 GMT, "Graham Knott" <g.knott@ntlworld.com
wrote:

That is funny. I kill filed him and haven't seen him until I cleared my Kill
file after the election.

But he is so sure I can't see him, because he was so objectionable.

So he is still being a jerk? Right?

 

[Peter Bennett]

On Sat, 06 Nov 2004 11:10:55 -0500, Chris <chrispol@videotron.ca>
wrote:

I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

Possibly...

Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

First, I see an error on the schematic - the AC ground should come
from pin 2 of the connector, not pin 3.

The board layout seems to have six diodes, but there are only four on
the schematic???

The board layout is poor - the capacitors at the input and output of
the regulators should be placed very close to the regulators - you
want short fat tracks between the hot side of the capacitors and the
regulator, and between the ground side of the capacitors and the
regulator. I can't see how you get from C2+ to IC2-in.

Autorouters can be useful, but they can also seriously mess up the
routing - things may be connected, but the tracks will go all over the
countryside. Strangely, they will often do a worse job on a simple
board like this than on a more complex board.

I don't know if Eagle has an auto-placer - but if so, don't bother
with it. Autoplacers were invented to appease the marketing
department, and rarely do anything useful, even on high-end CAD
systems.

I don't know what currents you expect to have on this board, but as a
matter of course, I would use .050, or even .100, tracks in a power
supply. There is lots of room on the board for Really Big tracks.

A comment on schematic drawing conventions - I consider it Bad
Practice to have 4-way junctions on a schematic - if the connection
dots go fuzzy (as they will after a few photocopies), it will be
unclear whether C1- and C5+ are just connected to each other, or if
they are also connected to ground. I would move the whole -12
regulator section right one grid position, so that you only have 3-way
connections - that would make it perfectly clear that C1- and C5+
connect to ground.


--
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

 

[Clarence]

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...

Chris wrote:
I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

No


Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

Just curious:
If your qualified to write a (really) basic book on electronics, shouldn't you
at least be able to trouble-shoot a simple power supply?

 

[Clarence]

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...

Chris wrote:
I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

No


Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

Your AC input, "X1" should be connected to pin 2, not as shown on pin 3!

 

[Graham Knott]

Clarence wrote:

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...
Chris wrote:
I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there...
does this matter?

No


Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm


Just curious:
If your qualified to write a (really) basic book on electronics,
shouldn't you at least be able to trouble-shoot a simple power supply?

He didn't ask for help troubleshooting!
This is what he asked if you read carefully.

the current doesn't seem to take the same

path as it does on breadboard, it seems to run here and there... does
this matter?

Try to be more positive with you criticisms and life can only get better.
Best regards.


--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

 

[Clarence]

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:EL9jd.194$Dn.14@newsfe3-gui.ntli.net...

Clarence wrote:
"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...
Chris wrote:
I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there...
does this matter?

No


Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm


Just curious:
If your qualified to write a (really) basic book on electronics,
shouldn't you at least be able to trouble-shoot a simple power supply?

He didn't ask for help troubleshooting!
This is what he asked if you read carefully.

the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

Other than the lines should probably be a little wider so a Power Supply to
minimize resistance it should have only a minimal effect?

Try to be more positive with you criticisms and life can only get better.
Best regards.

" I have drawn up a power supply on eagle, on bread board it all works
fine, but when I did a single layer pcb it didn't."

Sounds like a trouble shooting problem to me.
Also, the Schematic showed the input AC connector connected wrong!

Besides it was a valid question, not criticism.

While we are at it, why are 'YOU' so RUDE?

 

[Clarence]

"Clarence" <no@No.com> wrote in message
news:vbbjd.5532$zx1.2571@newssvr13.news.prodigy.com...

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:EL9jd.194$Dn.14@newsfe3-gui.ntli.net...
Clarence wrote:
"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...
Chris wrote:
I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there...
does this matter?
No
Schematic: http://chrispol.ath.cx:8080/power.jpg
Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

Just curious:
If your qualified to write a (really) basic book on electronics,
shouldn't you at least be able to trouble-shoot a simple power supply?

He didn't ask for help troubleshooting!
This is what he asked if you read carefully.

the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

Other than the lines should probably be a little wider so a Power Supply to
minimize resistance it should have only a minimal effect?

Try to be more positive with you criticisms and life can only get better.
Best regards.

" I have drawn up a power supply on eagle, on bread board it all works
fine, but when I did a single layer pcb it didn't."

Sounds like a trouble shooting problem to me.
Also, the Schematic showed the input AC connector connected wrong!

Besides it was a valid question, not criticism.

While we are at it, why are 'YOU' so RUDE?

I see that I was not replying directly to the OP due to the poor cropping of
the post you replied to with a curt "NO". Sorry about that. and your tag line
was in the way. Checking it made me question the need for the original post. I
see now that your RUDE response was because you missed the problem and wanted
to strike out in anger at someone.

I didn't mean to get in the line of fire.

BTW, there are a lot of GOOD books for beginners!

 

[Graham Knott]

Clarence wrote:

"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:EL9jd.194$Dn.14@newsfe3-gui.ntli.net...
Clarence wrote:
"Graham Knott" <g.knott@ntlworld.com> wrote in message
news:ga9jd.377$Wt.7@newsfe2-gui.ntli.net...
Chris wrote:
I have drawm up a power supply on eagle, on bread board it all
works fine, but when i did a single layer pcb it didn't. Now one
thing i noticed if i use autoroute the current doesn't seem to
take the same path as it does on breadboard, it seems to run here
and there... does this matter?

No


Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm


Just curious:
If your qualified to write a (really) basic book on electronics,
shouldn't you at least be able to trouble-shoot a simple power
supply?

He didn't ask for help troubleshooting!
This is what he asked if you read carefully.

the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there...
does this matter?

Other than the lines should probably be a little wider so a Power
Supply to minimize resistance it should have only a minimal effect?

Try to be more positive with you criticisms and life can only get
better. Best regards.


" I have drawn up a power supply on eagle, on bread board it all works
fine, but when I did a single layer pcb it didn't."

Sounds like a trouble shooting problem to me.
Also, the Schematic showed the input AC connector connected wrong!

Besides it was a valid question, not criticism.

While we are at it, why are 'YOU' so RUDE?

Oh dear,another troll.
I always give my best regards to trolls hoping that it makes their life
just a little bit happier.
Best regards Clarence.
--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

 

[petrus bitbyter]

"Chris" <chrispol@videotron.ca> schreef in bericht
news:jI6jd.60245$v03.1173786@wagner.videotron.net...

I have drawm up a power supply on eagle, on bread board it all works fine,
but when i did a single layer pcb it didn't. Now one thing i noticed if i
use autoroute the current doesn't seem to take the same path as it does on
breadboard, it seems to run here and there... does this matter?

Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

Printlayout is almost an art in itself and an autorouter is all but an
artist. This print is bad in two ways: The placement of some components is
wrong and the traces are improperly drawn and to thin. I don't want to
cover the whole print but I'll give some examples.

- The trace from the cathode D1 branches. One trace goes to the capacitors,
the other to the regulator. That's wrong. The trace should go from the diode
to the capacitors and then from the capacitors to the regulator.
- The 100nF decoupling capacitors should be near the regulators. Especially
a 7912 can go oscillate like hell when not carefully decoupled. Check the
datasheets for it.

An autorouter is not the correct tool to design printed circuit boards like
this. Its rules do not care for the rules of even this simple power suply
design.

petrus bitbyter


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[Clarence]

"Graham Knott" <g.knott@ntlworld.com> wrote in message
newsObjd.2147$QO4.768@newsfe1-gui.ntli.net...

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

My name is Graham Knott and I teach Electronics and Microcomputing in a third
rate school at Cambridge Regional College, situated in the city of Cambridge,
England. I need you money so send me $20 USD for my little reader.

Send money to:

Graham Knott 27, Edinburgh Road Cambridge CB4 1QR UK phone 01223 502751

Graham, Did I understand this right?

-------------------------------------

You see, I don't approve of begging!

 

[James T. White]

"Chris" <chrispol@videotron.ca> wrote in message
news:jI6jd.60245$v03.1173786@wagner.videotron.net...

I have drawm up a power supply on eagle, on bread board it all works
fine, but when i did a single layer pcb it didn't. Now one thing i
noticed if i use autoroute the current doesn't seem to take the same
path as it does on breadboard, it seems to run here and there... does
this matter?

Schematic: http://chrispol.ath.cx:8080/power.jpg

Board Layout: http://chrispol.ath.cx:8080/powerboard.jpg

Chris,

Some observations:

1) Your schematic and board don't seem to match. For example there are 6
diodes on the board and only 4 on the schematic. Also, the input power
connector seems to have all three pins connected on the board and only 2
connected on the schematic.

2) Have you verified the schematic and layout pin connections for all the
library components you have used against the component data sheets for the parts
you are using? It might seem strange, but I have seen an error here cause lots
of problems.

3) As some of the other responders have indicated, you should be using larger
traces for a power supply. You would also have better luck keeping the traces
short, by manually routing something this simple. You might have to add a wire
jumper here or there, but that is better than letting the autorouter run a trace
all around the board as it did for the input to your 7812. If you really must
use Eagle's autorouter, you should define a Net Class for your power traces
before turning the autorouter loose.

4) You might also try the Eagle news groups (eagle.support.eng or
eagle.userchat.eng). Since your circuit isn't a top secret design, consider
posting copies of your Eagle .brd and .sch files to make it easier for other
Eagle users to help you. At least that way, one could turn off the silkscreen
layer to see where the traces really go.

Good luck. I'd be interested to hear what the problem was when you find it.

--
James T. White

 

[Graham Knott]

Clarence wrote:

"Graham Knott" <g.knott@ntlworld.com> wrote in message
newsObjd.2147$QO4.768@newsfe1-gui.ntli.net...
--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm


My name is Graham Knott and I teach Electronics and Microcomputing in
a third rate school at Cambridge Regional College, situated in the
city of Cambridge, England. I need you money so send me $20 USD for
my little reader.

Send money to:

Graham Knott 27, Edinburgh Road Cambridge CB4 1QR UK phone 01223
502751

Graham, Did I understand this right?

-------------------------------------

You see, I don't approve of begging!
PLONK!

--
My most uptodate website is
http://homepage.ntlworld.com/g.knott/index.htm

 

[JeffM]

3)As some of the other responders have indicated, you should be using
larger traces for a power supply. You would also have better luck keeping
the traces short, by manually routing something this simple.
You might have to add a wire jumper here or there, but that is better than
letting the autorouter run a trace all around the board as it did for the
input to your 7812. If you really must use Eagle's autorouter, you should
define a Net Class for your power traces before turning the autorouter loose.

4)You might also try the Eagle news groups (eagle.support.eng or
eagle.userchat.eng). Since your circuit isn't a top secret design,
consider posting copies of your Eagle .brd and .sch files to make it easier
for other Eagle users to help you. At least that way, one could turn off
the silkscreen layer to see where the traces really go.
James T. White

Chris,
A lot of good stuff from James.
There is a school of thought on etching PCBs
that says the less copper you etch away, the more ecomomical the design;
make 'em as fat as clearance allows. (Your etchant lasts longer.)
Beefier copper is rarely a bad idea.

BTW, the EAGLE Autorouter never impressed me
--not even on a shortest-route basis.
As petrus said, to do a good job,
an autorouter has to know a lot of rules about physics
and the more you do before turning it loose, the better it does.