J
John Fields
Guest
On Tue, 17 Jan 2006 18:46:06 GMT, Rich Grise <richgrise@example.net>
wrote:
--
John Fields
Professional Circuit Designer
wrote:
???
--
John Fields
Professional Circuit Designer
R
Rich Grise
Guest
On Sun, 15 Jan 2006 00:16:11 +0000, ah wrote:
when he said, "Do you want to go right to sleep? or what?" she said, "What?"
;-)
Guy and his wife had 13 kids in 13 years. The wife was hard of hearing, so
when he said, "Do you want to go right to sleep? or what?" she said, "What?"
;-)
R
Rich Grise, but drunk
Guest
On Sun, 15 Jan 2006 07:40:46 +0000, ah wrote:
Cheers!
Rich
They're a pain in the ass. ;-)
Cheers!
Rich
P
Peter Hucker
Guest
On Tue, 17 Jan 2006 20:46:54 -0000, Rich Grise <richgrise@example.net> wrote:
--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com
If you're cross-eyed and have dyslexia, can you read all right?
[groan]
--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com
If you're cross-eyed and have dyslexia, can you read all right?
R
Rich Grise
Guest
On Tue, 17 Jan 2006 14:02:17 -0600, John Fields wrote:
enough - I saw that I misread his original question, so never
mind.
Sorry.
Rich
I tried to cancel this, but apparently an ohnosecond isn't quick
enough - I saw that I misread his original question, so never
mind.
Sorry.
Rich
A
ah
Guest
Rich Grise, but drunk wrote:
--
ah
You're inserting them backwards!
--
ah
A
ah
Guest
Rich Grise wrote:
--
ah
[groan]
--
ah
P
Peter Hucker
Guest
On Wed, 18 Jan 2006 15:56:11 -0000, ah <splifingate@gmail.com> wrote:
--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com
Bakers trade bread recipes on a kneadtoknow basis.
ROTFPMSL!
--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com
Bakers trade bread recipes on a kneadtoknow basis.
A
Abstract Dissonance
Guest
"Jasen Betts" <jasen@free.net.nz> wrote in message
news:3792.43cddbbd.5b72e@clunker.homenet...
easier to implement then my original idea by far. I'm not 100% it works for
all combinations but I do believe it can. The rows seem to "control" the
"parallel'ness" and the columns the "serial'ness" I'm going to go ahead and
try and prove it can get all the combinations and if I can do it then I'll
probably use your idea as it seems much much easier in the sense that I
don't really have to manufacture much as compared to having to make my own
switches(which I might do for fun one of these days but I'd rather get my
project done).
Thanks for the help,
AD
news:3792.43cddbbd.5b72e@clunker.homenet...
Cool. I believe it will allow for all combinations? If so then it is much
easier to implement then my original idea by far. I'm not 100% it works for
all combinations but I do believe it can. The rows seem to "control" the
"parallel'ness" and the columns the "serial'ness" I'm going to go ahead and
try and prove it can get all the combinations and if I can do it then I'll
probably use your idea as it seems much much easier in the sense that I
don't really have to manufacture much as compared to having to make my own
switches(which I might do for fun one of these days but I'd rather get my
project done).
Thanks for the help,
AD
J
Jasen Betts
Guest
On 2006-01-19, Abstract Dissonance <Abstract.Dissonance.hotmail.com> wrote:
a b c d e f g h i j k l m n
the only thing it can't do is devices with both leads disconnected
(another row with no conductor would allow that)
as the all-serial configuration uses has the most nodes (rows) and is
possible there are sufficient nodes.
suince all columns (device leads) are alike any device or group of devices
can be reversed or paralleled
since any device lead (column) can connect to any node (row)
any combination is possible. and most can be expressed in a number of
different ways.
Bye.
Jasen
a b c d e f g h i j k l m n
yes, it can also ne used with devices with three or more wires.
the only thing it can't do is devices with both leads disconnected
(another row with no conductor would allow that)
as the all-serial configuration uses has the most nodes (rows) and is
possible there are sufficient nodes.
suince all columns (device leads) are alike any device or group of devices
can be reversed or paralleled
since any device lead (column) can connect to any node (row)
any combination is possible. and most can be expressed in a number of
different ways.
Bye.
Jasen
J
Jon
Guest
Constantan has a temperature coffecicient of resistance of .000074
K^-1, so self heating would not be a problem. If you can't find a
supplier that will sell small quantities, buy a copper-constantan or
iron-constantan thermocouple and tear it apart
Regards,
Jon.
K^-1, so self heating would not be a problem. If you can't find a
supplier that will sell small quantities, buy a copper-constantan or
iron-constantan thermocouple and tear it apart
Regards,
Jon.
Y
Yukio YANO
Guest
Ian Bell wrote:
hit the wrong button. Still my point is that a large heat sink is not
needed.
A small copper trace would do fine in this application, and could easily
dissipate 1 watt into a PC board. The trick is how to make a
reproduceable low resistance mechanical connection to a very low Ohm
resistor. Soldering would work well.
Yukio YANO
that at 0.010 Ohms wouldn't dissipate all that much power at TEN Amps. I
hit the wrong button. Still my point is that a large heat sink is not
needed.
A small copper trace would do fine in this application, and could easily
dissipate 1 watt into a PC board. The trick is how to make a
reproduceable low resistance mechanical connection to a very low Ohm
resistor. Soldering would work well.
Yukio YANO
G
Geogle
Guest
Chuck Harris wrote:
electronics.basics group. My apologies.
used in normal 9V regulated supplies.
regulator, and measure the mains at the same time ?
Please correct me if I am wrong.
Thanks!!
I accidentally posted it to this group, my intention was
electronics.basics group. My apologies.
The tranformer I used is a step down one 9-0-9 seondary one, which is
used in normal 9V regulated supplies.
Do you mean to say it is difficult to power the meter from a step down
regulator, and measure the mains at the same time ?
Since I used a normal step down transformer, I don't see the danger.
Please correct me if I am wrong.
Thanks!!
P
Phil Allison
Guest
"Geogle"
** You are wrong !
A portable DMM must only be powered its *internal* battery. It is critical
for human safety that the battery remain inside the meter and impossible to
touch while the meter is in use.
Forget the externally supply idea completely !!.
It is lethal to YOU as well as the meter.
......... Phil
** You are wrong !
A portable DMM must only be powered its *internal* battery. It is critical
for human safety that the battery remain inside the meter and impossible to
touch while the meter is in use.
Forget the externally supply idea completely !!.
It is lethal to YOU as well as the meter.
......... Phil
G
Geogle
Guest
Phil Allison wrote:
It was to be used to monitor the mains supply, not for any other
purpose. Since nobody
is going to use it as a multimeter, I guess there won't be any problem
regarding personal safety. Keeping the personal safety apart is there
anything electrically wrong with
the setup ? Would any additions to the analog ( measurement ) inputs
help keep the instrument from damage ?
Thanks!!
Mains voltages, and wanted to keep it on for hours together.
It was to be used to monitor the mains supply, not for any other
purpose. Since nobody
is going to use it as a multimeter, I guess there won't be any problem
regarding personal safety. Keeping the personal safety apart is there
anything electrically wrong with
the setup ? Would any additions to the analog ( measurement ) inputs
help keep the instrument from damage ?
Thanks!!
P
Phil Allison
Guest
"Geogle"
** STOP being a stubborn shithead - Geogle.
** THAT is one of the MOST DANGEROUS purposes out.
** Totally bloody irrelevant !!!!!!!!!!!!
** You guess just like an ass goes " heee haw ...... "
** Insane question.
Wanna kill yourself - go right ahead.
.......... Phil
** STOP being a stubborn shithead - Geogle.
** THAT is one of the MOST DANGEROUS purposes out.
** Totally bloody irrelevant !!!!!!!!!!!!
** You guess just like an ass goes " heee haw ...... "
** Insane question.
Wanna kill yourself - go right ahead.
.......... Phil
G
Geogle
Guest
Phil, Thaks for the personal remarks 
Just reminds me of a posting asking if the google
groups are septic tanks!.
Being stubborn and s*d and ready to kill myself,
may I ask again what is fundamentaly wrong here ?
Is it possible to protect the meter electrically ?
Thanks.
Just reminds me of a posting asking if the google
groups are septic tanks!.
Being stubborn and s*d and ready to kill myself,
may I ask again what is fundamentaly wrong here ?
Is it possible to protect the meter electrically ?
Thanks.
P
Phil Allison
Guest
"Geogle"
** You are a stupid, fucking ass.
** The meter connects any external PSU to the AC supply rendering it a
LETHAL object to touch.
** Yes - use a damn battery, shithead.
NOW FUCK OFF !!!!!!!!!!!!
......... Phil
** You are a stupid, fucking ass.
** The meter connects any external PSU to the AC supply rendering it a
LETHAL object to touch.
** Yes - use a damn battery, shithead.
NOW FUCK OFF !!!!!!!!!!!!
......... Phil
G
Geogle
Guest
Phil Allison wrote:
Nobody is touching the meter or anything connected to it.
Please don't burst like Saddam
C
Chris
Guest
Geogle wrote:
Chuck Harris is almost certainly right.
Assuming you don't have any problems with the regulator itself, the
capacitive coupling or leakage current between the primary and
secondary of the transformer was probably responsible for frying your
7107 DVM chip. Voice of experience. Even a small capacitance between
primary and secondary in your step-down transformer completes a
capacitively coupled mains circuit which uses your IC as its load.
This is enough to let the smoke out. People keep trying exactly what
you're doing, and get the same frustrating results.
Your meter is made to have a floating power supply, and doesn't have
the internal protection that would be required to use a non-floating
supply. It would be possible to protect the meter somewhat by adding
100K resistors in series with the + and - leads, but that will ruin the
meter accuracy.
If I were in your shoes, I might use a small rechargeable lead-acid
12VDC battery along with a more efficient low dropout micropower
voltage regulator IC (the 7809 itself uses far more current than a 7107
with an LCD display). I'd just check the voltage on the battery
terminals every few weeks, and replace with a freshly charged battery
when the voltage dropped down to 11.2V or so. You also might want to
try 6 "D" batteries in series and forget the regulator.
Another possibility would be getting a step-down transformer with an
electrostatic shield to minimize capacitive coupling and leakage
current between transformer primary and secondary. This will get the
interwinding capacitance down to several pF, which should be OK for the
CMOS 7107.
If you want to "nuke it", try getting a "store-bought" linear 9V power
supply rated for medical use (protection on leakage current and
capacitive coupling built-in).
Of course, any precautions mentioned above about making it impossible
to accidentally touch the power source while connected to line voltage
are also correct. Use your head, and don't play with this unless you
know what you're doing.
Sorry again about the unfriendly welcome.
Good luck
Chris
Sorry about the rather unfriendly welcome to s.e.b. In fact, though,Phil, Thaks for the personal remarks
Just reminds me of a posting asking if the google
groups are septic tanks!.
Being stubborn and s*d and ready to kill myself,
may I ask again what is fundamentaly wrong here ?
Is it possible to protect the meter electrically ?
Thanks.
Chuck Harris is almost certainly right.
Assuming you don't have any problems with the regulator itself, the
capacitive coupling or leakage current between the primary and
secondary of the transformer was probably responsible for frying your
7107 DVM chip. Voice of experience. Even a small capacitance between
primary and secondary in your step-down transformer completes a
capacitively coupled mains circuit which uses your IC as its load.
This is enough to let the smoke out. People keep trying exactly what
you're doing, and get the same frustrating results.
Your meter is made to have a floating power supply, and doesn't have
the internal protection that would be required to use a non-floating
supply. It would be possible to protect the meter somewhat by adding
100K resistors in series with the + and - leads, but that will ruin the
meter accuracy.
If I were in your shoes, I might use a small rechargeable lead-acid
12VDC battery along with a more efficient low dropout micropower
voltage regulator IC (the 7809 itself uses far more current than a 7107
with an LCD display). I'd just check the voltage on the battery
terminals every few weeks, and replace with a freshly charged battery
when the voltage dropped down to 11.2V or so. You also might want to
try 6 "D" batteries in series and forget the regulator.
Another possibility would be getting a step-down transformer with an
electrostatic shield to minimize capacitive coupling and leakage
current between transformer primary and secondary. This will get the
interwinding capacitance down to several pF, which should be OK for the
CMOS 7107.
If you want to "nuke it", try getting a "store-bought" linear 9V power
supply rated for medical use (protection on leakage current and
capacitive coupling built-in).
Of course, any precautions mentioned above about making it impossible
to accidentally touch the power source while connected to line voltage
are also correct. Use your head, and don't play with this unless you
know what you're doing.
Sorry again about the unfriendly welcome.
Good luck
Chris