Chip with simple program for Toy

[Jon Slaughter]

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234c71f1de11c55b98a24d@news.individual.net...

In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build
a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning
about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time
trying
to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses statement.

He/She is implying that if you don't know even the basics of electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge buildering(Ok,
I
know he's ME but Rose is the one who brought up the bridge building) then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining
that
he should have spent more time on it. (What does ice hockey have to do
with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

Also we are getting off the point as if the guy is suppose to be the
best.
There are many EE's that don't even have a good understanding of their
own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

First off he's still in school... and second he said he didn't understand
voltage... that is only one concept in a huge number of concepts. Also we do
not know to what extent he didn't understand.

I can promise you that many EE graduates do not understand voltage but only
memorized formulas and defnitions..

So it isn't about what's right or wrong but what is real and not real. Sure
I would want everyone to have a little knowledge of everything... but that
isn't practical because then end up not being good at one thing

Did you ever stop to think that maybe the reason he didn't understand it was
that the professor that he took the class from that taught it didn't do a
good job? Do you also realize that there are many levels of understanding
it?

It's not that I don't agree with you that he should understand it and I'm
not even debating that.

But let me ask you something: Suppose he is the best bridge builder in the
world but he doesn't understand voltage... is it "ok"? Can we let it slide
or do we have to send the guy back to kindegarten to learn it? What if it
just can't do it and totally sucks at it? and he doesn't go around
pretending not too but just wants to build bridges... surely it's ok? It's
much better than 99% that don't know and don't give a shit about anything?


I think you guys are jumping to to many conclusions about the guy. We do not
know his circumstances and shouldn't judge him from one post on usenet that
says

"Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept."

In fact the question's he asks are quite fair and natural and means he has
an inquisitive mind. So instead of judge him we should try to help him
understand. As long as he doesn't pretend to know something and long as he
doesn't put peoples life at risk then it's not a problem. Sure we can hope
he will understand everything the first time and learn everything he can but
this isn't a fairy tale.

 

[Jon Slaughter]

"bgold12" <bgold12@gmail.com> wrote in message
news:16bcac37-c91c-4a5e-94e2-82fe21b9420b@m44g2000hsc.googlegroups.com...

Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept.

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles that affect the way they interact,
i.e. a charged particle induces a force on a surrounding charged
particle based on their charges (+e for a proton, -e for an electron,
and 0 for a neutron) and the distance and properties of the volume
between them), and I'm pretty sure I understand current, which is just
moving charges (I picture a bunch of electrons moving through a volume
between idle nuclei). But I don't get the concept of voltage. I know
it's produced from a separation of charges, and it is energy per
charge, or Joules/Coulomb, but where is the energy contained? How does
the coulomb of charged particles "have" this energy, and how is it
possible that there can be different amounts of energy associated with
a fixed amount of charged particles (i.e. you can have 10 joules/2
coulombs = 5 volts, but you can also have 20 joules/2 coulombs = 10
volts?)?

I kinda forgot to answer your questions:

Since you said you understand current, you do realize that I = Q/t? and
that if Q goes up and t goes down in proportion then I doesn't change? The
same thing is going on with voltage.

Analogy: If you have 10 N weight lifted up 3 feet then it has the same
potential energy as a 5 N weight lifted up 6 feet? (ok, not exactly since
the gravitational field is a bit weaker but close enough)

Remember that voltage isn't a fundamental quantity but is a function of more
than one.

V = J/C is one expression of V but it's also V = W/A as it is A*Ohm. (we get
the last two from ohms law)

I think you really need to think about it more. Take 2 C of charge and place
them at some distance apart, say it has 10 joules of energy, if you now move
them apart you increase the energy to maybe 20 joules? Or equivalently, but
with less information, we have went from 5V to 20V.

It is exactly analogous with many other physical quantities that depend on
more than one thing. If I have 80 C moving past a point in 2 second then
that is 40A but so is 40 C moving past a point in 1 second. I could also
have one electron moving past that point in 1/40C of a second and it would
also be equivalent to 40A.

Also if I reduce the time I move the 80C then from 2 seconds to 1 second(if
I slow them down) then I cut the current. In fact if I "freeze" everything,
even though I have 80C of charge sitting there, I have no current at all!


"The difference in voltage measured when moving from point A to point B is
equal to the work which would have to be done, per unit charge, against the
electric field to move the charge from A to B. "

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html

Note that it is a "per-unit" quantity that depends only on the distance in
the electric field. It doesn't depend on the amount of charge which is why
it is being divided out.

Think of it as energy per unit charge. Current gives us the other half of
the equation. If we know the energy per unit charge, or the voltage
difference, and we know the charge per second(along some path), or the
current, then if we multiply them we have

Energy/charge * charge/time = energy/time = power = work/time

i.e., V*I = P

If we had some idea of the time involved we could get the energy too.


If you want a microscopic concept then it is the energy contained per
electron in the electric field... (do you understand the electric field?)

The macroscopic concept is one of "force" or some "ability to do work"...
note that it is a mixed up concept because it's not fundamentally correct
but it is understanding by "consequence". (kinda like understanding anything
we have to associate it with things we know)

 

[Phil Allison]

<Gerbermultit00l@gmail.com>

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

** All depends on what DC current you are testing at.

Why not tell us ?



...... Phil

 

[Jon Slaughter]

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234caadfbe80755a98a255@news.individual.net...

In article <J7zEk.2061$Ws1.292@nlpi064.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234c71f1de11c55b98a24d@news.individual.net...
In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to
build
a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning
about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great
bridge
builder than build shitty ass bridges cause he spent to much time
trying
to
learn about electricity for some school requirements to "broaden
his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses
statement.

He/She is implying that if you don't know even the basics of
electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge
buildering(Ok,
I
know he's ME but Rose is the one who brought up the bridge building)
then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining
that
he should have spent more time on it. (What does ice hockey have to do
with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

Also we are getting off the point as if the guy is suppose to be the
best.
There are many EE's that don't even have a good understanding of their
own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

First off he's still in school... and second he said he didn't understand
voltage... that is only one concept in a huge number of concepts. Also we
do
not know to what extent he didn't understand.

Third year. He's specializing by now.

I can promise you that many EE graduates do not understand voltage but
only
memorized formulas and defnitions..

Irrelevant.

So it isn't about what's right or wrong but what is real and not real.
Sure
I would want everyone to have a little knowledge of everything... but
that
isn't practical because then end up not being good at one thing

It certainly is *EXPECTED* that a Junior in an engineering college
knows the rudiments of physics.

Did you ever stop to think that maybe the reason he didn't understand it
was
that the professor that he took the class from that taught it didn't do a
good job? Do you also realize that there are many levels of
understanding
it?

Possible, but irrelevant.

It's not that I don't agree with you that he should understand it and I'm
not even debating that.

Then what, exactly, are you debating?

But let me ask you something: Suppose he is the best bridge builder in
the
world but he doesn't understand voltage... is it "ok"? Can we let it
slide
or do we have to send the guy back to kindegarten to learn it? What if it
just can't do it and totally sucks at it? and he doesn't go around
pretending not too but just wants to build bridges... surely it's ok?
It's
much better than 99% that don't know and don't give a shit about
anything?

He's not the "best bridge builder". He's a college student who
apparently slept through physics. No, I don't want him building my
bridge.

I think you guys are jumping to to many conclusions about the guy. We do
not
know his circumstances and shouldn't judge him from one post on usenet
that
says

"Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept."

Yes, by the third year he's supposed to have had at least three
semesters of physics, one of which should have been E&M.

In fact the question's he asks are quite fair and natural and means he
has
an inquisitive mind. So instead of judge him we should try to help him
understand. As long as he doesn't pretend to know something and long as
he
doesn't put peoples life at risk then it's not a problem. Sure we can
hope
he will understand everything the first time and learn everything he can
but
this isn't a fairy tale.

Ok, I'm not judging him. His college should be boarded up.

You are making a lot of assumptions here from one small post about one
thing... You should be ashamed of yourself.

 

[Wim Lewis]

In article <93e80e6f-66bf-4ea5-96ca-c9f320931f3c@b1g2000hsg.googlegroups.com>,
jalbers@bsu.edu <jalbers@bsu.edu> wrote:

I am having a little trouble finding a "cheap" source for tunnel
diodes or tunnel diodes in general.

FYI, if all you want is to experiment with negative-resistance circuits,
you can get a vaguely tunnel-diode-like I-V characteristic by connecting
a pair of transistors:

http://www.zen22142.zen.co.uk/Theory/neg_resistance/negres.htm
http://users.tpg.com.au/users/ldbutler/NegResDipMeter.htm

And I hadn't run across this before today, but apparently you can get a
negative resistance out of a common PN2222A, too:

http://jlnlabs.online.fr/cnr/negosc.htm

--
Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1

 

[Anthony Fremont]

<cbarn24050@aol.com> wrote in message
news:1141688754.519023.231860@p10g2000cwp.googlegroups.com...

Anthony Fremont wrote:
"John Popelish" wrote:

Anthony Fremont wrote:

If you liked that, you should see the mess that hardware experts
make
when they try to write software. ;-)

Did that crack make you feel better about the difficulties you
have
with hardware design?

Given the commentary by cbarn24050 and maxfoo, I really don't
consider
mine to qualify as a "crack". In fact, I think it to be quite
appropriate. At least I wasn't publicly ridiculing anyone.

I wasn't trying to humiliate anyone either, he asked for comments. The
fact is needing multiple delays in a program is very commonplace and
it's normaly done with a few lines. What the author produced, however
well meaning, was just terrible. Thats not a problem for most people,

Honestly, I hadn't looked at it until now. Since he uses structs and a
long divide, I'm not real surprised on the space requirements.
Personally, I don't use C on a PIC since the hardware is not really up
for it without allot of hoop jumping by the compiler. The 18F type PICs
are more capable in this regard. So to each his own. I've used C on
8052's and I liked it, but it was a good compiler too (keil).

they just delete it in a heartbeat but a real beginner doesn't know
any
better. Iv'e shown him how to do it, if he did it again that way he
would see for himself but his pride has been hurt, that was never my
intention, and so he's gone on the defensive. Your right about
hardware
engineers messing up software but then again so do software engineers.

Everybody messes up software, 'cept me of course. ;-) I'm surprised
that John seemed to take offense to my comment. I really wasn't trying
to upset anyone, hence the smiley.

I would say that it's pretty selfless of Bruno to maintain a web site
for the benefit of others.

 

John Jardine. wrote:

pmlonline@gmail.com> wrote in message
news:1142366698.816585.196310@i40g2000cwc.googlegroups.com...
w2aew wrote:
Depending on "what" you need to measure on your signal, it might be a
good application for a lock-in amplifier. This technique is often used
to measure very small signals buried in noise.


Anyone have any thoughts on this Elliptic filter -

http://www.filter-solutions.com/active.htg/pos3.gif

It's the highest order Elliptic active filter I could find. It's not
bad, but would need at least 4 stages.

Paul

Opamp elliptics are a bit of a waste of time unless you have a particular
frequency to notch out.
Certainly useless if you want that 1MHz break frequency.
I'd guess a 30kHz filter might be appropriate.
Would suggest just stacking some simple 2nd or 3rd order Butterworth
designs.
john

Thanks for input. I see that you're 100% correct. Have you tried a
program called "Filter Solutions 2006?" It's a dream program. I'm very
disappointed in the Elliptic filters. The best bandpass filter I found
using a Pos SAB active implementation with lower & higher corner freq.
= 1KHz & 10KHz is a Chebyshev I. It requires only 4 op-amps for a 7th
order bandpass. Even after entering LM741 amp parameters I still get
-208db at 60Hz and -89db at 25KHz. Nearly 1db at 1KHz and 10KHz.
It's unbelievable! I'm curious what the disadvantages to a Pos SAB
active implementation since it uses less than half the parts-- 4
op-amps compared to 10. Here's the Spice Net List:


MULTIPLE ANALYSES
*
V1 1 0 AC 1
*V1 1 0 PULSE 0 1 0 5.033E-08 0
R111 1 2 4E+04
C112 2 7 1.069E-08
R113 2 0 2500
R109 2 3 1E+04
C101 3 4 1.504E-08
C102 4 5 1.828E-09
R103 5 0 5.737E+05
R104 4 7 2500
R106 6 0 1E+04
R107 6 7 1795
C108 4 0 2.183E-09
X101 5 6 7 OPAMP PARAMS: A=3E+11 B=4E+06
R211 7 8 2E+04
C212 8 13 6.06E-09
R213 8 0 5000
R209 8 9 1E+04
C201 9 10 1.001E-08
C202 10 11 7.2E-09
R203 11 0 1.051E+05
R204 10 13 5000
R206 12 0 1E+04
R207 12 13 2821
C208 10 0 1.469E-09
X201 11 12 13 OPAMP PARAMS: A=3E+11 B=4E+06
R311 13 14 2E+04
C312 14 19 6.288E-09
R313 14 0 5000
R309 14 15 1E+04
C301 15 16 7.512E-09
C302 16 17 1.434E-08
R303 17 0 7.002E+04
R304 16 19 5000
R306 18 0 1E+04
R307 18 19 2269
C308 16 0 9.47E-10
X301 17 18 19 OPAMP PARAMS: A=3E+11 B=4E+06
R401 19 20 1E+04
C402 20 21 1.451E-09
R403 21 0 1.557E+04
R404 20 23 3.513E+04
R406 22 0 1E+04
R407 22 23 7.787E+04
C408 20 0 1.451E-09
X401 21 22 23 OPAMP PARAMS: A=3E+11 B=4E+06
..AC DEC 200 0.1 2.5E+04
..PLOT AC VDB(23) -200 0
..PLOT AC VP(23) -200 200
..PLOT AC VG(23) 0 0.005
..TRAN 0.05 10 0
..PLOT TRAN V(23) -0.5 0.3
..END


*OpAmp Complex Model 1=+in 2=-in 10=Vo A=G*Bw Product(Hz)
B=Bw(Hz)
..SUBCKT OPAMP 1 2 10
+PARAMS: A=1.E+12 B=1.E+06
Rin 1 2 2.e+06
Cin 1 2 5.e-12
E1 3 0 1 2 1.0
Rp 3 4 1.0
Cp 4 0 {1/(2*PI*B)}
E2 5 0 4 0 {A/B}
Rout 5 10 500.
..ENDS OPAMP

 

[Jim Thompson]

On 14 Mar 2006 17:28:52 -0800, pmlonline@gmail.com wrote:

Thanks for input. I see that you're 100% correct. Have you tried a
program called "Filter Solutions 2006?" It's a dream program. I'm very
disappointed in the Elliptic filters.
[snip]

Designing elliptic filters CAN be a bit of a headache if you're
winging it.

If you really want to do it right may I suggest...

"Synthesis of Filters"
Herrero and Willoner
Prentice Hall EE Series Š 1966
Library of Congress 66-27547

Once upon a time I had the whole General Parameter Filters chapter
programmed into an ancient tape-card-reading hp calculator (or was it
TI... it was early '70's).

Probably ought to redo it in Larkin-suggested PowerBasic.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[techie_alison]

"Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message
news:20060321.0922.315797snz@pcserviceselectronics.co.uk...

Hopefully someone will direct you to a good company in the UK. Here in
the US I use PCB Express: http://www.pcbexpress.com/. While you don't
...
Considering you have what looks like only 1 capacitor on the bottom of the
board I would only bother with doing a

2 sided PCB
both sides solder mask
(makes soldering the components easier)
top side silkscreen ident
(mainly so the chip can be orientated correctly)

This at places like pcb-pool <http://www.pcbpool.com/> is a fairly
standard
and cheap variant and would be pretty good prices for your board size. Not
doing the solder masks on both sides does drop the cost further.

Quite a few do a faster turnaround than that, however get quotes from
each of them (quite a few do it online) for the whole PCB supply including
tooling.

The other thing that's crossed my mind is approaching a local educational
college, who often have the required equipment. I'll write over a letter
to
see if they'd like to give some students the opportunity to make a few ??
as
well as the college.

Depends on the college, and they don't work on the same type of deadlines
as you do, they are more likely to be interested if they can design the
circuit and/or layout as well. I would only approach them if the job was
not time critical in any way.

--
Paul Carpenter | paul@pcserviceselectronics.co.uk
http://www.pcserviceselectronics.co.uk/> PC Services
http://www.gnuh8.org.uk/> GNU H8 & mailing list info
http://www.badweb.org.uk/> For those web sites you hate

Hi Paul,

Thanks for replying. I'm waiting to hear back from 4 companies at the
moment to see what they come up with. They have the .brd and the images
below.

To save further debate, here's my original PCBs;
http://www.retro.dial.pipex.com/pest/pest_top.jpg and
http://www.retro.dial.pipex.com/pest/pest_bot.jpg . The fresh .brd is now
here; http://www.retro.dial.pipex.com/pest/pest.brd

Truth is I haven't the faintest idea what the specs are for those boards in
PCB terms. They're about 25mm x 30mm, and I'm guessing with soldermask, and
top silkscreen.

What I'm really trying to do is to get as many for as little ŁŁ as possible.
I guess the silkscreen (lettering) could go, not important. We were paying
about Ł80 for about 100 of those boards in 2 weeks or so. I've put this to
the 4 companies I've emailed.

It'd be great if anyone could tell me what the specs of these boards are.
Sorry to be a thick on this, this is a learning curve.

Thanks,

Aly

 

[Steve at fivetrees]

"techie_alison" <retro@dial.pipex.com> wrote in message
news:dvoqvb$5qn$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

"techie_alison" <retro@dial.pipex.com> wrote in message
news:dvon85$qlu$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

I've just been quoted Ł300 for 100 boards, what a bloody rip-off!! We
were
paying Ł80 before.

That almost certainly includes non-recurring charges such as photoplots and
tooling. Maybe get a quote for repeat orders? That would give you a better
comparison.

Steve
http://www.fivetrees.com

 

[Richard H.]

techie_alison wrote:

"Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message
news:20060321.0922.315797snz@pcserviceselectronics.co.uk...

Hopefully someone will direct you to a good company in the UK. Here in
the US I use PCB Express: http://www.pcbexpress.com/. While you don't

...
Considering you have what looks like only 1 capacitor on the bottom of the
board I would only bother with doing a

2 sided PCB
both sides solder mask
(makes soldering the components easier)
top side silkscreen ident
(mainly so the chip can be orientated correctly)

This at places like pcb-pool <http://www.pcbpool.com/> is a fairly

standard

and cheap variant and would be pretty good prices for your board size. Not
doing the solder masks on both sides does drop the cost further.

Quite a few do a faster turnaround than that, however get quotes from
each of them (quite a few do it online) for the whole PCB supply including
tooling.


The other thing that's crossed my mind is approaching a local educational
college, who often have the required equipment. I'll write over a letter

to

see if they'd like to give some students the opportunity to make a few ??

as

well as the college.

Depends on the college, and they don't work on the same type of deadlines
as you do, they are more likely to be interested if they can design the
circuit and/or layout as well. I would only approach them if the job was
not time critical in any way.

--
Paul Carpenter | paul@pcserviceselectronics.co.uk
http://www.pcserviceselectronics.co.uk/> PC Services
http://www.gnuh8.org.uk/> GNU H8 & mailing list info
http://www.badweb.org.uk/> For those web sites you hate



Hi Paul,

Thanks for replying. I'm waiting to hear back from 4 companies at the
moment to see what they come up with. They have the .brd and the images
below.

To save further debate, here's my original PCBs;
http://www.retro.dial.pipex.com/pest/pest_top.jpg and
http://www.retro.dial.pipex.com/pest/pest_bot.jpg . The fresh .brd is now
here; http://www.retro.dial.pipex.com/pest/pest.brd

Truth is I haven't the faintest idea what the specs are for those boards in
PCB terms. They're about 25mm x 30mm, and I'm guessing with soldermask, and
top silkscreen.

What I'm really trying to do is to get as many for as little ŁŁ as possible.
I guess the silkscreen (lettering) could go, not important. We were paying
about Ł80 for about 100 of those boards in 2 weeks or so. I've put this to
the 4 companies I've emailed.

It'd be great if anyone could tell me what the specs of these boards are.
Sorry to be a thick on this, this is a learning curve.

Thanks,

Aly

 

[Seymour Dupa]

Get a battery charger and plug it into the wall.
Connect the pump to the charger.

"T-n-T" <lildog@donobi.net> wrote in message
news:071220060930159427%lildog@donobi.net...

Can a 12v windshield wiper pump be run from a wall wart? I am putting
together a mist system for a terrarium, so it will run about 1 minute
2-3 times a day or so. If it will run from a wall wart any suggestions
would be great.

Todd

 

[DaveM]

"Seymour Dupa" <grumpy_44134@yahoo.com> wrote in message
news:h3Svh.195402$Yu6.107366@newsfe16.lga...

Get a battery charger and plug it into the wall.
Connect the pump to the charger.

"T-n-T" <lildog@donobi.net> wrote in message
news:071220060930159427%lildog@donobi.net...
Can a 12v windshield wiper pump be run from a wall wart? I am putting
together a mist system for a terrarium, so it will run about 1 minute
2-3 times a day or so. If it will run from a wall wart any suggestions
would be great.

Todd

Absolutely, it's possible. But the first thing you need to know is how much
current the pump draws when it's pumping.
Connect the pump to an auto battery and use your multimeter to measure the
current. Buy a wall wart that puts out 12 - 14 volts DC. The current rating of
the wall wart should be AT LEAST the current you measured being drawn by the
pump.
It's OK to go a bit higher than your measured current, but stay in the ballpark.
IOW, if your pump draws 1 amp, get a wallwart with current rating of 1 amp to
maybe 1.5 amps. If you get a regulated wallwart, the current rating doesn't
matter as long as it's at least 1 amp (as in the example).

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some days you're the dog, some days the hydrant.

 

[Stephen J. Rush]

On Tue, 30 Jan 2007 20:14:48 -0500, Seymour Dupa wrote:

Get a battery charger and plug it into the wall.
Connect the pump to the charger.

"T-n-T" <lildog@donobi.net> wrote in message
news:071220060930159427%lildog@donobi.net...
Can a 12v windshield wiper pump be run from a wall wart? I am putting
together a mist system for a terrarium, so it will run about 1 minute
2-3 times a day or so. If it will run from a wall wart any suggestions
would be great.

Or use an aquarium air pump to drive an old-fashioned perfume atomizer.

 

[Eeyore]

John Fields wrote:

Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:
John Fields wrote:

Fuck you, asshole pussy.

Mr Calm and Collected speaks again !

---
What makes you think I can't be calm, collected, and profane all at
the same time, motherfucker?

You're rarely calm and collected.

You're usually profane.

Graham

 

[Wim Lewis]

In article <pan.2007.03.03.03.06.16.601388@example.net>,
Rich Grise <rich@example.net> wrote:

On Fri, 02 Mar 2007 16:43:11 -0800, Marra wrote:
I would use a PIC with a PWM output driving the motor through a transistor
pair.

There's a new convention around here. Henceforth, any person posting "Use
a PIC" without providing your code, circuit, and development kit is
to be automagically deemed a "Troll".

In that case, from now on I will be suggesting the use of AVRs! I wouldn't
want to be a "troll".

More seriously ... while I agree that using a uC to generate an unvarying
square wave is overkill, I think you're diluting the term "troll"
into meaninglessness ... it doesn't just mean "someone who posted something
I don't agree with", you know.

Actually, the uC approach might not be so silly. DigiKey shows about the
same prices for PIC10F200s as for 555s, and the PIC would require fewer
external components (after programming, of course). Ditto the ATtiny11 and
some of the Zilog Z8s. Sheesh!

--
Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1

 

[Bruce Durdle]

H'es obviou'sly doing green'groc'er training cour'se's.

"Jerry Avins" <jya@ieee.org> wrote in message
news:dqWdnTxN8OzlyWrYnZ2dnUVZ_orinZ2d@rcn.net...

martin griffith wrote:
On Tue, 13 Mar 2007 22:45:13 GMT, in sci.electronics.design Apostrophe
Police <apopol@example.net> wrote:

On Tue, 13 Mar 2007 23:20:17 +0100, martin griffith wrote:
On 13 Mar 2007 13:46:36 -0700, in sci.electronics.design "werty"
werty@swissinfo.org> wrote:

I build test equip' .

So how do you test pizza's?

Test a pizza's what?

Apostrophes are not used for plurals, except in certain special
cases.

Thanks,
Rich Grise, Self-Appointed Chief,
Apostrophe Police

sorry, my bottle of wine cant' spell

So what's with hi's bottle? (Apostrophes are for possessives, no?)

Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ

 

[RST Engineering]

Bill ...

I would bet that most of the "confustion" comes from the conditions people
put on their answers to the question.

Some postulate a "tuner" between generator and load.

Some postulate a specific internal impedance of the generator.

Some postulate a specific length of feeder line (either lossless or
resistive, which is another parameter in and of itself).

Some postulate lots of other stuff, almost all of which is valid in the
context of their answer.

What exactly do we mean when we say that we have a "100 watt transmitter"?
What we are actually saying is that the transmitter will cause a resistor of
a specific value to dissipate 100 watts of energy when tied to the
transmitter output port and the transmitter keyed. Let's not muddy the
waters up by asking if we are talking about peak power, PE power, average
power, or whatnot. Let's just assume an unmodulated carrier putting out a
constant power into the resistor that gets just as hot as when 100 dc watts
(E*I) is pumped into it from a battery.

What value resistor? Whatever the designer/engineer/manufacturer specifies.
32 ohms? Sure. 50 ohms? No problem. 300 ohms? Certainly. Any competent
engineer can give you a specified power into a specified resistive load.

The crux of the question becomes, "What happens if my transmitter is
specified into a 50 ohm resistor and I put a 100 ohm resistor as the load?
How much "loss" do I get (or another way of asking that same question is how
much power is dissipated in the 100 ohm resistor)?"

The answer is that it is impossible to tell without making the measurement.
That may seem like a "wiggle" answer, but the truth of it is that the output
stage design of the transmitter will dictate how it handles a "VSWR load".
In some output stages, the output voltage will increase to the point of
nearly driving 100 watts into the 2:1 VSWR resistor. Some will shut
themselves down with a protection circuit. Some will go into parasitic
oscillation. Some will fry the output devices.

Now increase the magnitude (and probably the sign also) of the problem to
toss in a complex impedance instead of a resistive load and the confusion
factor goes up rapidly. What DOES that output stage do when the load has an
inductive component? Or a capacitive component? And both a resistive
component and an imaginary component that varies with frequency?

The simple answer to your question outside the "laboratory environment"
where everything is nicely matched and the internal impedances are set "just
so" is that there IS NO SINGLE RIGHT ANSWER to this simple question.

And that is most probably the cause of your confusion.

Jim



"billcalley" <billcalley@yahoo.com> wrote in message
news:1175199045.962572.290380@e65g2000hsc.googlegroups.com...


But here again, I'm probably not seeing the

entire picture here. What am I missing??

Confused!

-Bill

 

[Chuck]

Anthony Fremont wrote:

He also makes a big deal out of the particular op-amp chosen as (what
appears to be) a simple voltage follower. Any reason that you all can think
of?

I'm not seeing any out-of-the-ordinary
capabilities for the ADOP07CN. Why not
ask W6JFR?

Chuck

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

 

[Jon Slaughter]

"legg" <legg@nospam.magma.ca> wrote in message
news:70a733966enprncnkf6agki05mrto49veb@4ax.com...

Looks like there's a kook convention on SED.

Is there a common denominator ti killfile?

RL

If your interested,

http://www.stentorian.com/antispam/usenet.html
http://home.att.net/~marjie1/usenet.htm
http://tgos.org/newbie/xheader.html

You could find out who's doing this and report them to there host. Its
obviously the same mother fucker. It seems like an automatic application
that assembles messages from sources such as online reports and blogs or
maybe even old newgroup messages.

X-Complaints-To: abuse@telia.com

email them!!!