Chip with simple program for Toy

[Richard the Dreaded Liber]

On Wed, 25 May 2005 00:51:27 +0000, Bob Eldred wrote:

"John Douglas" <jdamja@sbcglobal.net> wrote in message

I had thought lead-free solder was considered safe.

I was prepared to let a 12 year old begin soldering (under supervision)
until I saw a warning on the back of the package stating that 'this
product contains a known carinogen to the state of Calif' (not exact
quote). Its standard stock lead-free solder from Radio Shack having
96% tin, 4% silver. (Where's the carcinogen in that?)

I am reluctant to let a child use this solder.
Does a safe solder exist?

As you can see, the nay sayers and laissez-faire republicans who could give
a crap about health as they guzzle their six packs and puff on their
cigarettes are out in force poo-pooing the state of California's warnings.

We don't have to, because the state of California's warnings are,
essentially, already poo-poo.

They would rather remain ignorant

HAH! Ignorant is as ignorant does.

than to be advised of some problems
that may occur in using that product. Ignorance is bliss and if anybody
tries to advise them, they shine it off as coming from the liberal nut
cases in granola land. The land of fruits, nuts, and flakes. Those
warnings may be overstated but, all they are, after all, are warnings to
let people know that there are certain chemicals involved that have
caused cancer in lab animals, albeit at high dose.
^^^^^^^^^

Well, on this morning's TeeVee Nooz, I noticed that hair dye has just been
given a clean bill of health. This is very likely because the rulemakers
don't want their Grecian Formula taken away. And they like their bleached
blondes.

You are free to do what you want,

Yeah, but for how long? How far are we from the point where everything not
specifically permitted is prohibited?

eat the
solder, breathe the fumes, whatever. But, a prudent person would take it
under advisement and probably use good ventillation when soldering and not
use it to solder water pipes or food implements without the proper non-toxic
and non-carcinogenic flux. It's common sense.
^^^^^^^^^^^^

Feh. If you used common sense, you wouldn't need Big Brother nanny state
to tell you when it's "safe" to wipe your own ass.

Thanks,
Rich

 

[John Fields]

On 25 May 2005 05:19:25 -0700, "MarkMc" <mmcnospam@yahoo.co.uk> wrote:

For my home brewery I need to know if a container has liquid past a
certain level, and if it is, turn on a pump.

Can anybody suggest a way of doing this? I don't really want to use
anything which floats in the liquid, I just need to know if the liquid
is past a certain point/level.

If there's anything "off the shelf" which I can screw in to the
container, then that would be fantastic.

---
I'd use a self-heated thermistor.

Since the heat capacity of beer is greater than that of air, when the
beer hits the thermistor it will suck heat out of it, causing its
temperature to fall, causing its resistance to rise. You can buy
thermistors in threaded mounts from Omega Engineering (pricey) which
will screw right into the container, and then with a couple of
resistors, a pot, a comparator, and an LED, you can put together a
circuit to do exactly what you want. Would you like a schematic?

--
John Fields
Professional Circuit Designer

 

[Art]

Fill out your organ donor card and give it a try. Let us know what your
symptomatic diagnostics verify to be true?
"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.05.25.18.22.48.871717@example.net...

On Wed, 25 May 2005 06:37:02 -0700, johnlee80 wrote:

Hi...

Just a question running through my mind. I know that a 12volt car
battery can't electrocute you.

What if i pass it through a step up dc converter to let say 110v for
the or 240v . Would the car battery now electrocute me if i were to
touch the neg and pos since the power supplied by the battery is almost
equivalent to the power supplied by the house electrical power source?

The way your question is phrased, the answer is no. The 12V from the
battery won't hurt you any more if it's supplying a load than if it's
not (this not counting open wounds (neglibile body resistance), hot
wrenches (you can weld with a 12V battery, under the right conditions),
and that sort of thing, which is a different question). But the 12V is
still 12V.

But the 110 or 240 definitely will at least give you a painful jolt,
and can very easily burn you or kill you.

Hope This Helps!
Rich

 

[Warren Weber]

"MarkMc" <mmcnospam@yahoo.co.uk> wrote in message
news:1117023565.354943.228810@g14g2000cwa.googlegroups.com...

For my home brewery I need to know if a container has liquid past a
certain level, and if it is, turn on a pump.

Can anybody suggest a way of doing this? I don't really want to use
anything which floats in the liquid, I just need to know if the liquid
is past a certain point/level.

If there's anything "off the shelf" which I can screw in to the
container, then that would be fantastic.

Regards,
Mark

Mark. Check out the "motor home" dealers. They use something to detect water
level in potable water tanks. W W

 

[Si Ballenger]

On 25 May 2005 05:19:25 -0700, "MarkMc" <mmcnospam@yahoo.co.uk>
wrote:

For my home brewery I need to know if a container has liquid past a
certain level, and if it is, turn on a pump.

Can anybody suggest a way of doing this? I don't really want to use
anything which floats in the liquid, I just need to know if the liquid
is past a certain point/level.

If there's anything "off the shelf" which I can screw in to the
container, then that would be fantastic.

Regards,
Mark

You cold attach some aquarium tubing to the bottom of the
container so the beer could flow in. Run the tubing up wards and
attach to a micro switch above the top of the container. At the
level where you want to activate the micro switch to run the
pump, make horozontal coils of the tubing so it will get heavier
as the coils fill and pull down on the micro switch to activate
the pump. There are other setups, but I like this one.

 

[R. Steve Walz]

Richard the Dreaded Libertarian wrote:

On Wed, 25 May 2005 00:51:27 +0000, Bob Eldred wrote:
"John Douglas" <jdamja@sbcglobal.net> wrote in message

I had thought lead-free solder was considered safe.

I was prepared to let a 12 year old begin soldering (under supervision)
until I saw a warning on the back of the package stating that 'this
product contains a known carinogen to the state of Calif' (not exact
quote). Its standard stock lead-free solder from Radio Shack having
96% tin, 4% silver. (Where's the carcinogen in that?)

I am reluctant to let a child use this solder.
Does a safe solder exist?

As you can see, the nay sayers and laissez-faire republicans who could give
a crap about health as they guzzle their six packs and puff on their
cigarettes are out in force poo-pooing the state of California's warnings.

We don't have to, because the state of California's warnings are,
essentially, already poo-poo.

They would rather remain ignorant

HAH! Ignorant is as ignorant does.

than to be advised of some problems
that may occur in using that product. Ignorance is bliss and if anybody
tries to advise them, they shine it off as coming from the liberal nut
cases in granola land. The land of fruits, nuts, and flakes. Those
warnings may be overstated but, all they are, after all, are warnings to
let people know that there are certain chemicals involved that have
caused cancer in lab animals, albeit at high dose.
^^^^^^^^^

Well, on this morning's TeeVee Nooz, I noticed that hair dye has just been
given a clean bill of health. This is very likely because the rulemakers
don't want their Grecian Formula taken away. And they like their bleached
blondes.

You are free to do what you want,

Yeah, but for how long? How far are we from the point where everything not
specifically permitted is prohibited?

eat the
solder, breathe the fumes, whatever. But, a prudent person would take it
under advisement and probably use good ventillation when soldering and not
use it to solder water pipes or food implements without the proper non-toxic
and non-carcinogenic flux. It's common sense.
^^^^^^^^^^^^

Feh. If you used common sense,
--------------------------

Which form of "sense" you clearly don't have.

you wouldn't need Big Brother nanny state
to tell you when it's "safe" to wipe your own ass.

Thanks,
Rich
-----------------------------

Rich is so immature and resentful of any authority that he is
slowly poisoning himself to prove he's "free". How Californian.

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

 

[R. Steve Walz]

MarkMc wrote:

For my home brewery I need to know if a container has liquid past a
certain level, and if it is, turn on a pump.

Can anybody suggest a way of doing this? I don't really want to use
anything which floats in the liquid, I just need to know if the liquid
is past a certain point/level.

If there's anything "off the shelf" which I can screw in to the
container, then that would be fantastic.

Regards,
Mark
----------------

Automatic washing machine's depth sensor. Works with a pressure
switch up top and a clear vinyl tube down into the basin. Any
appliance supply store. Adjust by moving the tube up and down.

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

 

[R. Steve Walz]

johnlee80@gmail.com wrote:

Hi...

Just a question running through my mind. I know that a 12volt car
battery can't electrocute you.

What if i pass it through a step up dc converter to let say 110v for
the or 240v . Would the car battery now electrocute me if i were to
touch the neg and pos since the power supplied by the battery is almost
equivalent to the power supplied by the house electrical power source?
-------------------

Easily.

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

 

[Tom Biasi]

<johnlee80@gmail.com> wrote in message
news:1117028222.451659.161560@f14g2000cwb.googlegroups.com...

Hi...

Just a question running through my mind. I know that a 12volt car
battery can't electrocute you.

What if i pass it through a step up dc converter to let say 110v for
the or 240v . Would the car battery now electrocute me if i were to
touch the neg and pos since the power supplied by the battery is almost
equivalent to the power supplied by the house electrical power source?

Power is the rate of doing work. It doesn't just jump out of a battery.

Study some about power.
Measure your body resistance and make calculations of current flow with 12
volts as a source.
Find a chart that shows the effects of current flow through the body.

Respect the potential energy in that battery.
Work safely,
Tom

 

[Bob]

"Tom Biasi" <tombiasi@REMOVEoptonline.net> wrote in message
news:Zhhle.2728$So7.1610@fe10.lga...

johnlee80@gmail.com> wrote in message
news:1117028222.451659.161560@f14g2000cwb.googlegroups.com...
Hi...

Just a question running through my mind. I know that a 12volt car
battery can't electrocute you.

What if i pass it through a step up dc converter to let say 110v for
the or 240v . Would the car battery now electrocute me if i were to
touch the neg and pos since the power supplied by the battery is almost
equivalent to the power supplied by the house electrical power source?

Power is the rate of doing work. It doesn't just jump out of a battery.

Study some about power.
Measure your body resistance and make calculations of current flow with 12
volts as a source.
Find a chart that shows the effects of current flow through the body.

Respect the potential energy in that battery.
Work safely,
Tom

DO NOT MAKE RESISTANCE MEASUREMENTS OF YOUR BODY WITH 12V !!!

As someone else pointed out, it only takes about 100mA through your heart to
kill you -- and maybe less.

Normally, the skin resistance is very high. If you're sweaty the it's less.
If you're under the epidermis then WATCH OUT. Don't take a chance unless you
really know what you're doing.

Bob

 

[Chris W]

Bob Eldred wrote:

. . .Those warnings may be overstated. . .



Overstated?! Now that is a serious understatement. I just received my

new model airplane engine in the mail the other day and it had that
cancer waning on the box. The warning was for the engine, not the fuel
or oil used to run the engine. I have no doubt that there is some
element, probably chromium, in some alloy in the parts of that engine
that, in the right form and sufficient dose, could cause cancer.
However, I also have no doubt that I could carry that engine, and or any
of it parts, in my had all day every day and never get cancer from it.
Certainly there would be no chance of getting cancer from any
conceivable use of that engine. That is why why these things that are
"known" to the state of California are such a joke. Now if they
restricted the warnings to things were there was really a chance of
getting cancer from the normal use or even abuse of a product, then I'm
sure they would be taken more seriously. There is a good chance of
getting seriously injured or even killed by that engine but it won't be
from cancer. If they want to put a warning on the box, they should warn
of the real dangers of using that engine, like chopping your fingers off
or killing some one by flying it into them.

--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com

 

[John Fields]

On 26 May 2005 15:07:37 -0700, "smokie" <stillbreezy@gmail.com> wrote:

how would the bandwidth of an inverting amplifier with a gain of -10
affect the rise time of a square wave input?

---
The higher the bandwidth, the faster the rise time.

--
John Fields
Professional Circuit Designer

 

[Joel Kolstad]

"Robert" <geronnimo@vp.pl> wrote in message
news:30a944c0.0505261537.4e66c10a@posting.google.com...

I would like to buy a programmer for my ATmega8 from ebay.com
for example like this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50915&item=7519278787&rd=1&ssPageName=WDVW
maybe somebody knows how long LPT cable I can use ?
I need about 60 ft.

Don't bet on it. If you're REALLY luck it might still work, but the LPT
interface was never designed to work over such distances.

I've seen installations where printers actually worked 100' away, but I've
also had personal experience where 25' away didn't work...

 

[John Popelish]

smokie wrote:

how does the treshold voltage change the transfer curve of a comparator?

Ideally, not significantly. Rail to rail designs often have a more
variable transfer function versus common mode voltage than others do,
because they may have two input differential amplifiers in parallel to
cover the entire supply range, and those two circuits may not match in
gain and speed. All this assumes that you are talking about
variations within the operating common mode range.

 

[Ban]

smokie wrote:

how would the bandwidth of an inverting amplifier with a gain of -10
affect the rise time of a square wave input?

Generally rise time(.1 to .9) will be around 1/3 of the invers of the
bandwidth, so if that amp has 1MHz BW, the rise-time will be 330ns.
--
ciao Ban
Bordighera, Italy

 

[R. Steve Walz]

Bob wrote:

"Tom Biasi" <tombiasi@REMOVEoptonline.net> wrote in message
news:Zhhle.2728$So7.1610@fe10.lga...

johnlee80@gmail.com> wrote in message
news:1117028222.451659.161560@f14g2000cwb.googlegroups.com...
Hi...

Just a question running through my mind. I know that a 12volt car
battery can't electrocute you.

What if i pass it through a step up dc converter to let say 110v for
the or 240v . Would the car battery now electrocute me if i were to
touch the neg and pos since the power supplied by the battery is almost
equivalent to the power supplied by the house electrical power source?

Power is the rate of doing work. It doesn't just jump out of a battery.

Study some about power.
Measure your body resistance and make calculations of current flow with 12
volts as a source.
Find a chart that shows the effects of current flow through the body.

Respect the potential energy in that battery.
Work safely,
Tom



DO NOT MAKE RESISTANCE MEASUREMENTS OF YOUR BODY WITH 12V !!!

As someone else pointed out, it only takes about 100mA through your heart to
kill you -- and maybe less.

Normally, the skin resistance is very high. If you're sweaty the it's less.
If you're under the epidermis then WATCH OUT. Don't take a chance unless you
really know what you're doing.

Bob
----------------------

A few volts arm to arm administered with needles will stop your
heart.

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

 

[w_tom]

Duty cycle changes the energy of frequencies (sine waves of
different frequencies) that, together, form a square wave.
Learn about Fourier series (from math books) to better
appreicate the concept. As duty cycles change, then more
energy may appear in a higher frequency sine wave. Those
higher frequencies dissipate more energy in the transformer.
Best to have only a frequency at the ideal transformer
frequency. But then duty cycle would not change to adjust
output voltage. Less efficiency for better voltage
regulation. This and other compromises are why the switching
power supply cannot have 100% efficiency.

Unloaded switching power supplies do not break. Some
switching power supplies do not operate well in a no load
condition; so power supply shuts down without damage.
Characteristics of each design. Important is even how the
transfomer is designed. Numerous design compromises are
involved. Many switching power supplies work just fine under
no load. Which ones? The long list of numeric specs should
be provided for each switching power supply model.

Chokes permit energy at some frequency to be converted to
energy at other frequencies. Chokes permits the design to
intergrate filters with sharper cutoff frequencies. Chokes
are essential to better EMC solutions. Chokes can store
energy at certain key operational points. But chokes cost
money. Some power supplies are designed to cut costs rather
than meet standard criteria. To better appreciate the value
and energy conservation of chokes, learn fundamentals of
filter design. Concepts that also better explain what happens
as duty cycle changes.

BradBrigade wrote:

First of all, I'm trying to figure out how switching power supplies
work (the ones in PCs). I've found very basic info, but I want more
technical stuff. If anyone has some good links please let me know.
These are questions I have yet to find an answer for.

Anyway, here's my question. One thing I read was that the output
voltage of the supply is fed back to the PWM which changes it's duty
cycle accordingly to keep the output voltage constant. But I thought
that the input-to-output ratio of a transformer is fixed. If the PWM
is outputting 100V at 20KHz to a 10:1 transformer, you get out 10V at
20KHz, right? What does it matter what the duty cycle is? It's still
100V at 20KHz. What am I missing?

Second, why does a switching power supply break without a load?

Third, in all my years in electronics, I have never used a choke, now I
see them all over these power supplies. Can someone clue me in about
what they do, and why they are in these things?

I appreciate any info at all. Thanks a lot.

 

[Joel Kolstad]

Hi BradBrigade,

"BradBrigade" <sizzlefist@hotmail.com> wrote in message
news:1117222764.995442.200520@g14g2000cwa.googlegroups.com...

Anyway, here's my question. One thing I read was that the output
voltage of the supply is fed back to the PWM which changes it's duty
cycle accordingly to keep the output voltage constant. But I thought
that the input-to-output ratio of a transformer is fixed. If the PWM
is outputting 100V at 20KHz to a 10:1 transformer, you get out 10V at
20KHz, right?

Yes, the _instantaneous_ output voltage of the transformer is still 10V.

What does it matter what the duty cycle is? It's still
100V at 20KHz. What am I missing?

The output of the transformer is feed to some form of filtering -- usually a
series inductor and parallel capacitor -- and the output voltage then found
across the capacitor is the _average_ of the input voltage. So... 10V
instantaneous output from the transformer at 100% duty cycle gets you 10V
across the capacitor... 50% duty cycle would get you 10V instantaneous output
from the transformer for half the time and 0V for the other half of the time,
so this averages to 5V across the capacitor... etc...

(This is somewhat simplified; in actuality the voltage change a little due to
diode drops, active device losses, etc. -- the feedback loops jiggles the duty
cycle until the right regulated output voltage appears, though.)

Second, why does a switching power supply break without a load?

Because the designers are either (1) ignorant or (2) cheap.

OK, actually, not all switchers have no-load problems. What happens -- and
this is for the most basic example you could come up with, something like a
simple buck converter -- is that during the time that the transformer (or
inductor) is being fed current, flux (current) builds up in it. When the
switch controlling this current is turned off, the current (flux) in the core
starts dropping. The rate at which it drops is proportional to the load...
bigger load (lower impedance), faster current drop. With a "big enough" load,
the current goes all the way to zero. On the next switching cycle, the
current ramps up again to some current, then ramps down to zero, etc. -- this
repeats forever.

Now, with a small load, while the current does drop, it doesn't go all the way
to zero before the next switching cycle. Now current ramps up again and -- if
one isn't careful in design -- the current ends up higher than it was at the
turn-off point of the last cycle. It drops a little again (but not to zero),
and now at the next turn on the current is driven even higher. Sooner or
later, the inductor saturates, which tends to look almost (but not quite) like
a short circuit to the driver. That driver starts having massive current run
through it, heats up, and sooner or later dies.

Hence, there's some minimum load that causes the switcher to change from
discontinuous to a continuous mode of operation, and for loads lighter than
this you can get into trouble.

If you think about it for a moment, it's clear you could simply detect the
current in the core and quit driving it when you start to approach
saturation -- this simple solution is what "current mode" switchers do, and
they usually don't have no-load problems. In fact, if you think about it even
more, even in the case with regular "voltage mode" feedback, since the current
in the core is increasing, the output voltage will as well, so the feedback
regulator should keep clamping down on the duty cycle so as to avoid
saturating the core. The problem here is that the 'transfer function' of the
power supply from input to output is different when it's operating in this
'continuous' mode rather than 'discontinuous' mode, and it takes more effort
to build a feedback network that can keep the entire 'loop' stable in both
modes (and without starting to become slightly sophisticated in your feedback
network, making a power supply no-load stable often degrades the step
response, which isn't desirable). Hence, for both the sake of cost (the extra
feedback network circuitry) or merely ignorance on the part of the designer,
some power supplies turn over and die when run without a minimum load.

Third, in all my years in electronics, I have never used a choke, now I
see them all over these power supplies. Can someone clue me in about
what they do, and why they are in these things?

Ummm... you know what capacitors do, right? You 'feed' them a current and
this causes charge to accumulate within them such that a voltage appears
across them? Inductors are their 'dual' -- you 'feed' them a voltage and this
causes flux to accumulate within them such that a current flows throughout
them. Hence, just like a capacitor, inductors can be used to store energy.
With an inductor, by varying the duty cycle of a voltage across it, you can
'charge up' the inductor to some arbitrary average current and then 'dump'
this into a load to get a corresponding voltage. This makes it easy to make
regulated _voltage_ power supplies, whereas a similar approach with capacitors
would get you a regulated _current_ power supply.

I'd suggest checking out Abraham Pressman's switching power supply book. It's
not cheap, but it's written by a guy who seemed far more intent on building
working power supplies than doing more theoretical research. It does of
course have some math in it, but even someone with one semester of caclulus
will probalby be able to follow it.

---Joel

 

[Joel Kolstad]

W_Tom,

"w_tom" <w_tom1@hotmail.com> wrote in message
news:429783F3.D82F5CE9@hotmail.com...

Duty cycle changes the energy of frequencies (sine waves of
different frequencies) that, together, form a square wave.

Uh, no, it doesn't! If I give you a periodic signal of a certain frequency,
it doesn't matter WHAT it 'looks' like, its Fourier spectrum will ONLY contain
the fundamental frequency and harmonics. Changing what it 'looks' like (e.g.,
the duty cycle of a square wave) only changes the magnitudes of the harmonics.

This and other compromises are why the switching
power supply cannot have 100% efficiency.

Overall most switchers lose far more efficiency in the switches than they do
in the core.

Unloaded switching power supplies do not break.

Some do. Although you could convince me that such switchers are, by
definition, poorly designed.

Chokes permit energy at some frequency to be converted to
energy at other frequencies. Chokes permits the design to
intergrate filters with sharper cutoff frequencies. Chokes
are essential to better EMC solutions. Chokes can store
energy at certain key operational points.

Where do you get this stuff? Some generic "everything you wanted to know
about electronics" encyclopedia? A lot of what you say is factually correct,
just not at all relevant to the discussion at hand.

To better appreciate the value
and energy conservation of chokes, learn fundamentals of
filter design.

Someone who's an expert at filter design could very well not know the first
thing about switcher design. They're pretty disparate areas of design, and
really only start to overlap somewhat when you discuss output filtering,
resonant designs, etc.

---Joel Kolstad

 

[w_tom]

A switching power supply could easily provide those voltages
without the expensive transformer. But a power supply must
also perform many other functions including galvanic
isolation. For computers, this breakdown voltage must exceed
1000 volts. Therefore the transformer (to send power to the
load) and the feedback circuit (to regulate output voltage and
other functions) must both provide that galvanic isolation:
First and foremost for human safety reasons. Second for
transistor safety.

BradBrigade wrote:

OK, I got it, the output is filtered to create a stable voltage that is
the average of the duty cycle. But now I'm wondering, what is the
purpose of the transformer? If you want to convert 100V to 10V, why
not filter the output straight from a PWM with a 10% duty cycle?
What's the difference?

Thanks a lot.