Chip with simple program for Toy

[Terry Pinnell]

"Everett X. Wang" <everteq@sbcglobal.net> wrote:

Hi All,

I am working on a home project that needs to supply a 24V power to a
brushless motor controller. The motor draws 24V with current less then 3.0A
and my 12 to 24V DC to DC power supply is rated 700W. But when I connect the
things together, the power supply will shut it down. My guess is the motor
controller draws a high current at a very short time that overwhelmed the
power supply, since my current meter indicated only 3 A from the 12V side.

Can anyone give me a suggestion how to make my power supply work? Can I add
a large capacitor at the power supply output? I also tried an other DC 2 DC
(rated 4.5A output) power supply. The result is even worse. (It worked for a
few seconds vs. minutes). My application is a mobile one and I can't use a
desktop power supply. The power source is from 12V lead acid battery. Any
solution to my problem?

Thanks in advance.

Guessing that the converter's oscillator is being affected by feedback
from the motor. I'd try
1) Adequately rated diode in series with motor
2) The high value capacitor you suggested, plus a 10nF ceramic
3) Fresh 12V battery (existing may have highish internal resistance)
4) Choke-based filters on input and/or output of converter
5) Combinations of the above

This assumes it really is impossible to get a second 12V battery to
give you the requisite 24V, or a 12V motor!

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

Paul wrote:

Is it possible to build a circuit for generating high voltage at
very low current equivalent to that of a simple electrostatic
discharge?

We need to know what you're trying to drive. Electrostatic effects
begin at 1KV. Needing 1KV at 1uA is very different than needing
500KV at 100uA!!! A solid state VandeGraaff machine is a huge
project.

Maybe you can use one of these 10KV supplies:

http://www.goldmine-elec-products.com/prodinfo.asp?number=G9695


(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 206-789-0775 unusual phenomena, tesla coils, weird sci

 

[R. Steve Walz]

Spaceman wrote:

The only web forum site for Electrical and Electronic Engineers!

Yeh right! I had a look at it, thats one really dead site.

Trying to get people there....then it will be great
----------------

You ridiculous ego-ridden little shit, they are already here!

-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

 

[Terry Pinnell]

John Fields <jfields@austininstruments.com> wrote:

On Mon, 06 Dec 2004 21:02:26 +0000, Terry Pinnell
terrypinDELETE@THESEdial.pipex.com> wrote:


I think your copy/paste was scrambled. I'm no LT Spice expert, but for
example I reckon all those WIRE lines should have a syntax like this:
WIRE -704 -384 -704 -624
WIRE -704 -688 -464 -688
etc
IOW, 1 per line, 4 co-ordinates each, ending with a Return character.

---
Yup, thanks...
Schematic now looks fine - a lot easier on the eye than

http://sowell.ecs.fullerton.edu/jag/fuelingsys/tester120404.jpg <g>

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

Bahremu wrote:

First RTFM.
If you had RTFM, you would realize that the KMV has a feature that
allows
you to press some keys on the keyboard to change the active system.

Go read your KVMs manual and find the easiest and cheapest solution.
my kvm extender does not support the hotkeys offered by my kvm switch

 

Bahremu wrote:

First RTFM.
If you had RTFM, you would realize that the KMV has a feature that
allows
you to press some keys on the keyboard to change the active system.

Go read your KVMs manual and find the easiest and cheapest solution.
my kvm extender does not support the hotkeys offered by my kvm switch

 

[CFoley1064]

Subject: Re: Need help in stablizing a power supply
From: "Everett X. Wang" everteq@sbcglobal.net
Date: 12/7/2004 1:41 AM Central Standard Time
Message-id: <C8dtd.29943$zx1.12286@newssvr13.news.prodigy.com

Thanks for the suggestion. I got a 38,000 uF cap. But voltage is rated 25V .
Should it be OK for 24V application? I don't think I will go over 25V.

Thanks.

Everett

I wouldn't do it, but it's up to you. I would guess your peak voltage will
probably be above 25V, which will probably smoke the cap, and might smite your
converter in rage on its way to electronics heaven.

You can get a 4700ľF 35V 20% Axial-Lead Electrolytic Capacitors for $5.29 USD
at RadioShack (Catalog #: 272-1022).

Also, you can get a couple of 0.47 Ohm/5W 5% Wirewound Resistors for $1.59 USD
each at RadioShack (Catalog #: 271-130 ). Put them in parallel to get about
0.23 ohms.

For a less money/more time/probably equal or better quality tradeoff, try
Mouser.com.

Good luck
Chris

 

[JL Hart]

Maurine O. wrote:

arunsahlam@gmail.com wrote in message news:<1101987990.663067.277800@f14g2000cwb.googlegroups.com>...


Hi,

I would like to control arund 100 electric switches from my PC.
Can someone guide me on this.

Thanks in advance

Arun Sahlam




well how do you want to control them.? and what sort of switches are
they.? and what do they control.?, what kind of hardware do you have
hooked up to your computer at the moment.???......You could use a
microcontroller to do this, but some information regarding your
existing infrastructure would be useful

There is a book, perhaps out of print, from TAB books "Building Your Own

Universal Computer Interface" by Bruce Chubb, that would provide a bunch
of outdated information to get you started. The ISBN # is 0-8306-3122-4.

Also, a look at the data sheet for an 82C55 programmable interface
controller is interesting for historical content. It will point out the
many good reasons for using a micro controller.

Maurine's questions are also valid. On what level of interface are you
looking to implement? Parallel port? Serial port? Mother board plug-in
card? Speed?
Then comes the question of user interface software on the PC. Is this
something that you would prefer "off the shelf", or will you develop
this application software?

 

[Terry Pinnell]

"Jag Man" <Jag_Man653R-E-MOVE@hotmail.com> wrote:

Tell me, do SPICE and similar programs typically have models of
the generic 555 that are good enough for desigh calcs like this?

Yes.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[ali]

Thanks everyone, this was enlightening...

My main motivation was not to solve the problem, but to learn some
electronics. If the problem got solved, that's just a side-effect .
So based on all of your kind input, i think i will change the project a
bit.

I think i'll just hook the float to a rheostat or pot (i don't really
know which at the moment) and hook the pot to an LED display which
would be downstairs and would tell me about the level of water. I can
turn off the pump manually with the help of the display. Surely, i hope
this is electronics and not just plumbing .

Anyway, i'll read up on all these links and be back when i get stuck...
Thanks once again...

 

[John Popelish]

James Howe wrote:

On Thu, 09 Dec 2004 03:42:59 GMT, Robert Monsen <rcsurname@comcast.net
wrote:

James Howe wrote:
I'm new to electronics so I'm not great at circuit analysis. I've
been reading some books and I understand some simple circuits, but the
circuit below has me somewhat confused.[...]
Here is the schematic:
56k 1k
+4v *--/\/\/\--+--/\/\/\----------------------+
| |
| / e
| /
| \ ------| Q1 (PNP)
| -|\ /e \
+------| \ / \ c
| \--/\/\/\-|Q2 (PNP) |
+------| / 47 \ |
| +|/ \c |
| / LM324 | |
0v *----------+ +--------+
|
|
|
|
.01 uf 100 |
-12v *--------]|-------------------/\/\/\-------+


[...]

For the above, you know that the opamp will try to keep the junction
between the 56k and 1k resistor at 0V, so the current through the 56k
resistor will be

4V / 56k = 71.429uA

[...]


Thanks for the explanation, but I have one question. I'm familiar with
OPAMP's used with negative feedback and it sounds like this is what you
are describing when you say that the OPAMP will attempt to keep the
junction of th 56k and 1k at 0v. However, what confuses me is that the
output of the OPAMP goes into two PNP transistors where the emitters are
connected to the 1k resistor. In conventional electron flow, wouldn't the
current be coming through the 1k, and through the emitters exiting through
the base at the 47 ohm resistor and out through the collector connected to
the 100 ohm resistor? In this arrangement I don't see how there can be
negative feedback into the inverting pin since it would seem that the
current couldn't flow through the base/emitter junctions back towards the
1k resistor.

I must be misunderstanding something.

When the opamp output voltage is two diode drops more negative than
the right end of the 1k resistor, the Q2 begins to conduct, supplying
base current to Q1 which also begins to conduct, and all that current
passes through the 1k resistor, making its right end more negative
than its right. This process continues till the voltage at the
junction of the two resistors balances at zero volts, so that all the
current passing through the 56k resistor also passes through the 1k
resistor, while the voltage across the 56k resistor is 4 volts.

At the same time almost all that current also passes through the 100
ohm resistor. The only part missing is the small base current being
injected by the opamp output into Q2 which becomes part of the emitter
current of Q1 but does not make it to the collectors.
--
John Popelish

 

[hotkey]

they change the angle of the wings, untill unsafe when they switch off
altogether


"Rodney Kelp" <rodneykelp605@hotmail.com> wrote in message
news:C6KdnZAscfxp2FPdRVn-hQ@adelphia.com...

With wind speeds from zero to tornado, how do windmills maintain voltage
and
more importantly frequency when hooked up to a grid? If they put out 3
phase
there must be a phase sync problem.


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.690 / Virus Database: 451 - Release Date: 5/22/2004

 

[aberte@gmail.com]

Hi uncle_seb:
i'm a university student. We use: Communication Systems, by A.B.
Carlson. I found it very complete, but too hard for an introductory
course on signal processing (although the complete title:
"Communication Systems: an Introduction to Signal and Noise in
Electrical Communication"
http://www.mhhe.com/engcs/electrical/carlson/). If you are just
interested on soft introduction to signal theory with digital signal
processing orientation, there is a book available online:

http://www.dspguide.com

with some math but not hard to understand. I hope you'll find this
useful.
Happy Christmas

 

[John Popelish]

James Howe wrote:

I'm new to electronics so I'm not great at circuit analysis. I've been
reading some books and I understand some simple circuits, but the circuit
below has me somewhat confused. This circuit is used to convert an input
voltage into a constant current. The capacitor in the circuit is actually
hooked into a timer to periodically discharge it, but I'm not interested
in that part of the circuit at this time.

Basically what I'm trying to figure out is voltage and current at parts of
the circuit. I've tried my best to produce an ASCII version of the
circuit, please excuse my crude attempt. The circuit basically consists
of a handful of resistors, two 2N4126 PNP transistors, a .01uf capacitor
and an LM324 op amp. The positive voltage is a control voltage and can
range from approximately 0v to 5v. The negative voltage is fixed at -12v.

In my reading, I've seen descriptions on how to compute voltage and
current through NPN as well as PNP transitors. However, all the examples
have a positive (or negative for PNP) voltage going into the collector and
the emitter connected to ground. This circuit is different because the
collector is connected to negative voltage through a capacitor and the
emitter is connected to a positive voltage. I'm not sure the best way to
attack this circuit for the purpose of figuring out voltage and current
values. Any help or tips you can provide would be greatly appreciated.

Here is the schematic:

56k 1k
+4v *--/\/\/\--+--/\/\/\----------------------+
| |
| / e
| /
| \ ------| Q1 (PNP)
| -|\ /e \
+------| \ / \ c
| \--/\/\/\-|Q2 (PNP) |
+------| / 47 \ |
| +|/ \c |
| / LM324 | |
0v *----------+ +--------+
|
|
|
|
.01 uf 100 |
-12v *--------]|-------------------/\/\/\-------+

And if the picture is munged, here is a description:

A +4v supply is connected to a 56k and 1k resistor in series. Between the
56k and 1k resistor a connection is made to the LM324 OPAMP on the
inverting input. The non-inverting input is connected to ground. The
output of the OPAMP connects to a 47 ohm resistor and into the base of a
2N4196 PNP Transistor. The emitter is connected to another 2N4146 and the
emitter of the second transistor connects to the other end of the 1k
resistor. The collectors are tied together and are connected to a 100 ohm
resistor which is connected to a .01 uf capacitor and finally to a -12v
power supply. As I said earlier, in the full circuit, the capacitor is
periodically discharged.

Thanks.

--
James Howe

Contact: http://public.xdi.org/=James.Howe

The main simplifying assumption to make is that the opamp will use its
output to keep its two inputs at the same voltage. Since the
noninverting input is at 0 volts, the output will use the output
darlington pair of PNP transistors to hold its - (inverting ) input at
zero volts, also.

The second simplifying assumption is that the two inputs of the opamp
draw no current.

So any current that arrives at from the positive control voltage (+4)
through the 56k resistor must be sucked up by the 1k emitter resistor
in such a way that the node between those two resistors stays at zero
volts. The two transistors are connected to multiply the current
gains of the transistors, so that the base current of Q2 is so small
that you can neglect it. So essentially all the current through the
1k resistor also passes through the two collectors to the 100 ohm
resistor. And this current equals the current through the 56k
resistor with the control voltage minus zero volts across it,
regardless of variations on the voltage on the collectors of the two
PNP transistors. So the capacitor charges with a current that equals
the current through the 56k resistor.

--
John Popelish

 

[Lord Garth]

"hotkey" <adennel@jeack.com.au> wrote in message
news:41b9a782_1@news.iprimus.com.au...

they change the angle of the wings, untill unsafe when they switch off
altogether

Long ago, Popular Science had an article about a system that corrected for
this
problem. Sorry I can't quote when. I believe it used a slip ring in a
novel way.

 

[Rich Grise]

On Sat, 11 Dec 2004 07:33:31 +0000, Lord Garth wrote:

"hotkey" <adennel@jeack.com.au> wrote in message
news:41b9a782_1@news.iprimus.com.au...
they change the angle of the wings, untill unsafe when they switch off
altogether


Long ago, Popular Science had an article about a system that corrected for
this
problem. Sorry I can't quote when. I believe it used a slip ring in a
novel way.

Variable-pitch props have been almost routine for quite some time. But if
you're running a windmill, is it "correct" to call the turbine blades a
"prop?"

Thanks,
Rich

 

[Peter Lawton]

"Rich Grise" <rich@example.net> wrote in message
newsan.2004.12.11.08.03.57.609592@example.net...

On Sat, 11 Dec 2004 07:33:31 +0000, Lord Garth wrote:


"hotkey" <adennel@jeack.com.au> wrote in message
news:41b9a782_1@news.iprimus.com.au...
they change the angle of the wings, untill unsafe when they switch off
altogether


Long ago, Popular Science had an article about a system that corrected
for
this
problem. Sorry I can't quote when. I believe it used a slip ring in a
novel way.

Variable-pitch props have been almost routine for quite some time. But if
you're running a windmill, is it "correct" to call the turbine blades a
"prop?"

Thanks,
Rich
And being equally pedantic, if they aren't milling then are they mills?

Peter

 

[Raul]

Hi, I realize you want to build something yourself but you might try a
marine store to get some ideas. They have all kinds of water
activated/deactivated switches for pumps.
Raul

 

[Rich Grise]

On Sat, 11 Dec 2004 21:50:56 +0000, Peter Lawton wrote:

"Rich Grise" <rich@example.net> wrote in message
On Sat, 11 Dec 2004 07:33:31 +0000, Lord Garth wrote:
"hotkey" <adennel@jeack.com.au> wrote in message
they change the angle of the wings, untill unsafe when they switch off
altogether

Long ago, Popular Science had an article about a system that corrected
for
this
problem. Sorry I can't quote when. I believe it used a slip ring in a
novel way.

Variable-pitch props have been almost routine for quite some time. But if
you're running a windmill, is it "correct" to call the turbine blades a
"prop?"

And being equally pedantic, if they aren't milling then are they mills?

I think that might depend on what your definition of "mill" is:
-----------------------
Webster's Revised Unabridged Dictionary (1913) [web1913]

Mill \Mill\ (m[i^]l), n. [L. mille a thousand. Cf. Mile.]
A money of account of the United States, having the value of
the tenth of a cent, or the thousandth of a dollar.

Mill \Mill\, n. [OE. mille, melle, mulle, milne, AS. myln,
mylen; akin to D. molen, G. m["u]hle, OHG. mul[=i], mul[=i]n,
Icel. mylna; all prob. from L. molina, fr. mola millstone;
prop., that which grinds, akin to molere to grind, Goth.
malan, G. mahlen, and to E. meal. [root]108. See Meal flour,
and cf. Moline.]
1. A machine for grinding or comminuting any substance, as
grain, by rubbing and crushing it between two hard, rough,
or intented surfaces; as, a gristmill, a coffee mill; a
bone mill.

2. A machine used for expelling the juice, sap, etc., from
vegetable tissues by pressure, or by pressure in
combination with a grinding, or cutting process; as, a
cider mill; a cane mill.

3. A machine for grinding and polishing; as, a lapidary mill.

4. A common name for various machines which produce a
manufactured product, or change the form of a raw material
by the continuous repetition of some simple action; as, a
sawmill; a stamping mill, etc.

5. A building or collection of buildings with machinery by
which the processes of manufacturing are carried on; as, a
cotton mill; a powder mill; a rolling mill.

6. (Die Sinking) A hardened steel roller having a design in
relief, used for imprinting a reversed copy of the design
in a softer metal, as copper.

7. (Mining)
(a) An excavation in rock, transverse to the workings,
from which material for filling is obtained.
(b) A passage underground through which ore is shot.

8. A milling cutter. See Illust. under Milling.

9. A pugilistic. [Cant] --R. D. Blackmore.

Edge mill, Flint mill, etc. See under Edge, Flint,
etc.

Mill bar (Iron Works), a rough bar rolled or drawn directly
from a bloom or puddle bar for conversion into merchant
iron in the mill.

Mill cinder, slag from a puddling furnace.

Mill head, the head of water employed to turn the wheel of
a mill.

Mill pick, a pick for dressing millstones.

Mill pond, a pond that supplies the water for a mill.

Mill race, the canal in which water is conveyed to a mill
wheel, or the current of water which drives the wheel.

Mill tail, the water which flows from a mill wheel after
turning it, or the channel in which the water flows.

Mill tooth, a grinder or molar tooth.

Mill wheel, the water wheel that drives the machinery of a
mill.

Roller mill, a mill in which flour or meal is made by
crushing grain between rollers.

Stamp mill (Mining), a mill in which ore is crushed by
stamps.

To go through the mill, to experience the suffering or
discipline necessary to bring one to a certain degree of
knowledge or skill, or to a certain mental state.

Mill \Mill\, v. t. [imp. & p. p. Milled; p. pr. & vb. n.
Milling.] [See Mill, n., and cf. Muller.]
1. To reduce to fine particles, or to small pieces, in a
mill; to grind; to comminute.

2. To shape, finish, or transform by passing through a
machine; specifically, to shape or dress, as metal, by
means of a rotary cutter.

3. To make a raised border around the edges of, or to cut
fine grooves or indentations across the edges of, as of a
coin, or a screw head; also, to stamp in a coining press;
to coin.

4. To pass through a fulling mill; to full, as cloth.

5. To beat with the fists. [Cant] --Thackeray.

6. To roll into bars, as steel.

To mill chocolate, to make it frothy, as by churning.

Mill \Mill\, v. i. (Zo["o]l.)
To swim under water; -- said of air-breathing creatures.

Mill \Mill\, v. i.
1. To undergo hulling, as maize.

2. To move in a circle, as cattle upon a plain.

The deer and the pig and the nilghar were milling
round and round in a circle of eight or ten miles
radius. --Kipling.

3. To swim suddenly in a new direction; -- said of whales.

4. To take part in a mill; to box. [Cant]

Mill \Mill\, n.
1. Short for Treadmill.

2. The raised or ridged edge or surface made in milling
anything, as a coin or screw.

Mill \Mill\, v. t.
1. (Mining) To fill (a winze or interior incline) with broken
ore, to be drawn out at the bottom.

2. To cause to mill, or circle round, as cattle.

WordNet (r) 2.0 [wn]

mill
n 1: a plant consisting of buildings with facilities for
manufacturing [syn: factory, manufacturing plant, manufactory]
2: Scottish philosopher who expounded Bentham's utilitarianism;
father of John Stuart Mill (1773-1836) [syn: James Mill]
3: English philosopher and economist remembered for his
interpretations of empiricism and utilitarianism
(1806-1873) [syn: John Mill, John Stuart Mill]
4: machine that processes materials by grinding or crushing
[syn: grinder]
5: the act of grinding to a powder or dust [syn: grind, pulverization,
pulverisation]
v 1: move about in a confused manner [syn: mill about, mill
around]
2: grind with a mill; "mill grain"
3: produce a ridge around the edge of; "mill a coin"
4: roll out (metal) with a rolling machine

The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]

mill

Arithmetic and Logic Unit

Easton's 1897 Bible Dictionary [easton]

Mill
for grinding corn, mentioned as used in the time of Abraham
(Gen. 18:6). That used by the Hebrews consisted of two circular
stones, each 2 feet in diameter and half a foot thick, the lower
of which was called the "nether millstone" (Job 41:24) and the
upper the "rider." The upper stone was turned round by a stick
fixed in it as a handle. There were then no public mills, and
thus each family required to be provided with a hand-mill. The
corn was ground daily, generally by the women of the house (Isa.
47:1, 2; Matt. 24:41). It was with the upper stone of a
hand-mill that "a certain woman" at Thebez broke Abimelech's
skull (Judg. 9:53, "a piece of a millstone;" literally, "a
millstone rider", i.e., the "runner," the stone which revolves.
Comp. 2 Sam. 11:21). Millstones could not be pledged (Deut.
24:6), as they were necessary in every family.
------------------

;-)

Cheers!
Rich

 

[Roger Johansson]

Hans-Bernhard Broeker <broeker@physik.rwth-aachen.de> wrote:

Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

The margin between these two thresholds on stimulus strength is
probably too small to be safe for everyday usage other than in a
*very* closely controlled environment (say, within shouting distance
of an ICU, with trained medical personnel controlling the apparatus,
given a rather specific medical indication for doing it).

There is a big margin between what can be sensed by the skin and what
could kill you, or damage your body in any way.

But, of course you need to have a brain to do anything with electricity,
just like you need a brain to cross a street without getting killed.

Using normal precaution is of course necessary, like using a small battery
to drive this circuit, not the mains power. And start testing on a suitable
part of the body, like a leg.


--
Roger J.