PRC as a amplifier in GPS question.

[Phil Allison]

"Franc Zabkar" <fzabkar@optussnet.com.au> wrote in message
news:udinkvcmspfovah38uktd5471ficjrpgl9@4ax.com...

** Peanuts. A PC plus monitor peaks at 100 + amps.

Chalk and cheese. 100A for a split second is nothing compared to 8A
over several seconds.

** That is why I said that a start up resistor for a motor may need to "a
whopper".

However switch on surges for sizable transformers and de-gauss coils
lasts many cycles, dim lights and blows slo- blow fuses.



............. Phil

 

[gary drummond]

Here is a link for Java and C++. You might find others through
the publishers or author lists...

http://mindview.net/Books


Gary

Davo wrote:

Hello,

I am looking for active newsgroups, productive user friendly tutorials, good
weblinks, and local private tutors (Melbourne Australia) in the programming
language C. The two news groups athome.aus.programming and
athome.aus.programming.c++ dont seem to have much activity. Any
information or advice will be much appreciated.

Regards

Dave

 

[Rod Speed]

Phil Pierotti <Phil.dot.Pierotti@SoftHome.dot.NET> wrote in message news:MPG.19b6bf5cbcf0831398968a@news.swiftdsl.com.au...

Tune for minimum smoke?

Always essential with any project.

Also, one last question - so far I've been unable to source even
a naked transformer which produces exactly 9VAC@1.5A output.

So I'm wondering which way I should lean?

You use a 2A transformer.

Exactly the correct output voltage but higher AMPs

Yep.

(and assume the internal electronics will only draw what's needed),

Thats what happens. The current rating is what the
transformer can supply while still producing that voltage.

or vice-versa?

Nope.

In article <bigu91$99dp5$1@ID-69072.news.uni-berlin.de>,
rod_speed@yahoo.com says...

Phil Pierotti <Phil.dot.Pierotti@SoftHome.dot.NET> wrote in message news:MPG.19b6a52f13bdada5989689@news.swiftdsl.com.au...

I guess then I'm essentially SOL looking for an existing
wall-wart, and therefore need to assemble my own.

Yep.

Not knowing anything about assembling power transformer
circuits (or any caveats therein), is it as simple as:

240V wall Socket-> OZ power plug -> cable -
transformer -> cable with appropriate plug for my device?

Yep. Best to use a plastic box so you dont
have to bother with earthing a metal box.

pack it in a project box of suitable size (with ventilation)

That last isnt really necessary.

and have fun?

You forgot the tune for minimum smoke step.

Have fun when ready, Gridly.


In article <bifvoe$8raoo$1@ID-69072.news.uni-berlin.de>,
rod_speed@yahoo.com says...

Phil Pierotti <Phil.dot.Pierotti@SoftHome.dot.NET> wrote in message news:MPG.19b5fa29baa0eec7989688@news.swiftdsl.com.au...

I have a device I bought while in the US which requires
an input of 9VAC@1.5A. The US being the center of the
known universe (and also for the sake of minimizing costs,
I assume) the wall-wart it came with only takes 110V input.

If I tried to plug in a wall-wart with 16VAC@1.5A output, I
assume one part or another in my device will fry quite nicely.

Really depends on the device.

AC wall warts are usually used when the device needs to generate
more than one DC supply internally, like with modems etc.

As such they may not care about the higher AC input, but if its got
a 5V DC internal rail, the regulator to 5V may well get pretty hot
just because its dropping rather more voltage down to 5V.

 

[Mark van der Eynden]

Phil Pierotti <Phil.dot.Pierotti@SoftHome.dot.NET> wrote in message news:<MPG.19b6bf5cbcf0831398968a@news.swiftdsl.com.au>...

Tune for minimum smoke?

Also, one last question - so far I've been unable to source even a naked
transformer which produces exactly 9VAC@1.5A output.

So I'm wondering which way I should lean?

Exactly the correct output voltage but higher AMPs (and assume the
internal electronics will only draw what's needed), or vice-versa?

Thanks.

I'd be inclined to open it up and check for the conditions previously
mentioned.

If we are stuck with the 9 volt option, I might wonder if it really
needs the 1.5 amps. Buy one transformer and measure the
voltage/current. If it seems to be closer to 1.5 amps, but a second
transformer and put it in parallel.

Then again, depending upon the $ aspect it might be cheaper to buy 2
transformers and skip the rest. (but just make sure you put them in
parallel, not 'shorted series').

Cheers,

Mark

 

[John G]

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bigf9f$9a829$1@ID-69072.news.uni-berlin.de...

Rob Judd <judd@ob-wan.com> wrote in message
news:3F4B871C.D091B9C@ob-wan.com...
Brian Goldsmith wrote:
Mainlander <*@*.*> wrote

I seem to recall there are differing ways of implementing RS232,
some work on +/- 5Volts which doesn't meet standard.

RS232 is THE standard.Any protocol that does not meet the
requirements of this written standard is NOT RS232 but some other
variant with perhaps,as we have read,differing voltage levels etc.

The rot set in with Japanese printers, where they
started dropping lines and using small plugs.

Nope, DEC started using a minimum number of lines
LONG before Jap serial printers ever showed up.

9-pin RS-232 ain't RS-232 either,
no matter what voltage is present.

There were never many lines used in the 25 pin plug.
It had all the lines necessary for normal RS232 and all the lines necessary
for Current Loop and some to spare.
In an early combined Parralel printer and Serial port IBM found there was
not room for 2 25 pin connectors so used a 9 pin for the serial port, which
was adequate even if slightly off spec and it has since become a defacto
standard as it does the job commpletely and takes up less space.
--
John G

Wot's Your Real Problem?

 

[budgie]

On Wed, 27 Aug 2003 02:13:16 +1000, Rob Judd <judd@ob-wan.com> wrote:

Brian Goldsmith wrote:

"Mainlander" <*@*.*> wrote

I seem to recall there are differing ways of implementing RS232, some
work on +/- 5Volts which doesn't meet standard.

*** RS232 is THE standard.Any protocol that does not meet the
requirements of this written standard is NOT RS232 but some other
variant with perhaps,as we have read,differing voltage levels etc.
Brian Goldsmith.

The rot set in with Japanese printers, where they started dropping lines
and using small plugs. 9-pin RS-232 ain't RS-232 either, no matter what
voltage is present.

Actually, the rot set in with the first PC - or even earler attempts
at such a device. The standard defines interfaces for/between Data
Terminal Equipment (DTE's) and Data Communications Equipment (DTE's).
Not for pea-seas or anything like that. Modems are examples of DCE's
(and i can't think of any other ATM), while terminal devices -
teleprinters etc - are DTE. DTE connect to DCE, but DCE don't connect
to DCE and DTE don't connect to DTE.

OK, so a Com port on a PC has to to talk to a printer (terminal, DTE)
so it ought to be a DCE configuration.

But a PC Com port wants to talk to a modem, which means the port needs
to be configured as a DTE.

Can't be both, as the pinout is different. So a decision was made
(presumably by IBM-ers) that a PC port was a DTE. From that point on,
confusion started to reign in the printer world.

 

[Mark Fergerson]

Duane C. Johnson wrote:

<snip>

I have made an inverter that works on single
PV cells. See:
http://www.redrok.com/images/pvcellinv01.gif

This is a newer version of a ckt you previously posted
using LEDs as PV cells to get the +5V, yes? I saw the older
one some time ago and lost your name and the URL or I'd have
asked you sooner; can you please provide a description of
the ckt's operation?

I'm interested because I have a sh*tload of LEDs lying
around unused and would like to fiddle with the ckt because
I think it's more amenable to miniaturization than other
(vaguely) similar ckts I've seen, and the limited lifetine
of standard Si PV cells (I want to try a bunch of red LEDs
for the low V supply part instead of a Si PV). BTW, any data
on the lifetime and efficiency of LEDs used in this manner?

Mark L. Fergerson

 

[Rod Speed]

"budgie" <budgie@nowhere.cantech.net.au> wrote in message news:3f4c5b5f.1081378@news.cantech.net.au...

On Wed, 27 Aug 2003 02:13:16 +1000, Rob Judd <judd@ob-wan.com> wrote:

Brian Goldsmith wrote:

"Mainlander" <*@*.*> wrote

I seem to recall there are differing ways of implementing RS232, some
work on +/- 5Volts which doesn't meet standard.

*** RS232 is THE standard.Any protocol that does not meet the
requirements of this written standard is NOT RS232 but some other
variant with perhaps,as we have read,differing voltage levels etc.
Brian Goldsmith.

The rot set in with Japanese printers, where they started dropping lines
and using small plugs. 9-pin RS-232 ain't RS-232 either, no matter what
voltage is present.

Actually, the rot set in with the first PC

Nope, long before that.

- or even earler attempts at such a device.

Much earlier in fact.

In fact there had been a general trend to serial printers with
minis long before the PC ever showed up, which then did a
giant step backwards to centronix parallel printers again.

Serial printers never really did take off on PCs except
with daisywheel printers and then later with lasers.

The standard defines interfaces for/between Data Terminal
Equipment (DTE's) and Data Communications Equipment (DTE's).

In fact it was primarily a standardisation of the interface with modems.

Not for pea-seas or anything like that.

Modems are examples of DCE's
(and i can't think of any other ATM),

Thats just the same thing in different words,
modems are data comms equipment.

while terminal devices - teleprinters etc - are DTE. DTE connect to
DCE, but DCE don't connect to DCE and DTE don't connect to DTE.

There's been null modems around for a long time before the PC.

OK, so a Com port on a PC has to to talk to a printer (terminal, DTE)

Thats just mangling the original clear distinction
as was seen with minis long before the PC.

so it ought to be a DCE configuration.

Nope, it aint data comms equipment.

Neither were minis either.

But a PC Com port wants to talk to a modem, which
means the port needs to be configured as a DTE.

Can't be both, as the pinout is different. So a decision was
made (presumably by IBM-ers) that a PC port was a DTE.

That was seen long before the PC with minis.

From that point on, confusion started to reign in the printer world.

Nope, it had happened long before that, most obviously with
serial printers on minis when there was no modem involved.

Mainframes too, tho that gets even more messy.

 

Rob wrote:

Guys, can anyone point me in the direction of an Australian supplier of
small (M3/4/5) screws and nuts with integral captive washers.

TIA

Try

Universal Fasteners
60 Grand Junction Rd 5084
Kilburn
Ph: (08) 8300 8700
Fax: (08) 8300 8777

--

David

 

[John Crighton]

On Wed, 27 Aug 2003 16:49:13 +1000, "TT" <noname@noname.com> wrote:

I would like to vary the speed of a 12V 4W DC motor (brush type). I've
tested the motor and under load, it pulls less than 1A.

I was thinking of using an LM317T adjustable voltage regulator with trimpot
to do this. Is there any problems associated with using the regulator to
vary the speed? Do I need to add any extra protection to the output of the
regulator?

Thanks.



Hello TT,

have a look here
http://www.solorb.com/elect/solarcirc/pwm1/
This PWM type of control is a much nicer way
to control the speed of your DC motor.
Oatley, Dick Smith and others places have similar
PWM motor control kits if you don't want to scratch
build from your junkbox parts.
The problem with using a regulator to vary the
voltage applied to the motor is low starting torque
at low voltage for slow running. At low speed
the voltage across the regulator is greatest.
Volts times Amps equals Power (wasted power)
The regulator warms up.
Better to just switch the motor on and off rapidly
by varying the "on" to "off" time, called the
mark to space ratio.

Have Fun,
John Crighton
Hornsby

 

[William P.N. Smith]

Mark Fergerson <mfergerson1@cox.net> wrote:

Duane C. Johnson wrote:
I have made an inverter that works on single
PV cells. See:
http://www.redrok.com/images/pvcellinv01.gif

can you please provide a description of
the ckt's operation?

Gee, that's easy, and it's not even my circuit:

U1{A,B,C} make up an oscillator, coupled to U1{D,E,F}, which provide a
driver to the two FETs.

Q1 drives a simple step-up through D1 to provide 5V to drive U1, the
two LEDs provide a shunt to keep the voltage from rising too high.

Q2, T1, D3 provide a step-up with a transformer boost to charge the
battery. D2 provides overcharge protection and bootstraps U1.

The two LEDs can apparently also provide some bootstrap via their PV
action.

and the limited lifetine
of standard Si PV cells

Decades aren't enough?

--
William Smith wpns@compusmiths.com N1JBJ@amsat.org
ComputerSmiths Consulting, Inc. www.compusmiths.com

 

[Gary]

There are a few circuits at this site: http://www.cpemma.co.uk/index.html ,
some linear, some PWM.


Gary


"TT" <noname@noname.com> wrote in message
news:3f4c5474$0$15135$afc38c87@news.optusnet.com.au...

I would like to vary the speed of a 12V 4W DC motor (brush type). I've
tested the motor and under load, it pulls less than 1A.

I was thinking of using an LM317T adjustable voltage regulator with
trimpot
to do this. Is there any problems associated with using the regulator to
vary the speed? Do I need to add any extra protection to the output of the
regulator?

Thanks.

 

[Duane C. Johnson]

Hi William;

"William P.N. Smith" <wpns@compusmiths.com> wrote:

Mark Fergerson <mfergerson1@cox.net> wrote:
Duane C. Johnson wrote:
I have made an inverter that works on single
PV cells. See:
http://www.redrok.com/images/pvcellinv01.gif

can you please provide a description of
the ckt's operation?

Gee, that's easy, and it's not even my circuit:

U1{A,B,C} make up an oscillator, coupled to U1{D,E,F},
which provide a driver to the two FETs.

Q1 drives a simple step-up through D1 to provide 5V
to drive U1,

I chose a BS107 small MOSFET for it's very low gate
voltage. There are better MOSFETs but that's the one I had.

the two LEDs provide a shunt to keep the voltage from
rising too high.

The LEDs don't do regulation as there is 10K in series
with them.

I use them as a bootstrap power source to get the
oscillator supply voltage over about .9V. The oscillator
I have here is about the lowest VCC I can get to run
without using germanium transistors.

Anyway once the voltage gets to .9V or so the oscillator
starts and Q1 converts power from the PV cell to something
over about 2.5V where the large power MOSFET takes over.

Q2, T1, D3 provide a step-up with a transformer boost
to charge the battery. D2 provides overcharge protection
and bootstraps U1.

Yep, crude but effective.

The two LEDs can apparently also provide some bootstrap
via their PV action.

Yes, a few uA of charge current.
The green LEDs I use have the capability of generating
1.7V. However the the oscillator consumes this current
so I put 2 LEDs in series to get some improvement in
starting time.

and the limited lifetime of standard Si PV cells

Decades aren't enough?

--
William Smith wpns@compusmiths.com N1JBJ@amsat.org
ComputerSmiths Consulting, Inc. www.compusmiths.com

Thanks!
Duane

--
Home of the $35 Solar Tracker Receiver
http://www.redrok.com/electron.htm#led3X [*]
Powered by \ \ \ //|
Thermonuclear Solar Energy from the Sun / |
Energy (the SUN) \ \ \ / / |
Red Rock Energy \ \ / / |
Duane C. Johnson Designer \ \ / \ / |
1825 Florence St Heliostat,Control,& Mounts |
White Bear Lake, Minnesota === \ / \ |
USA 55110-3364 === \ |
(651)426-4766 use Courier New Font \ |
redrok@redrok.com (my email: address) \ |
http://www.redrok.com (Web site) ===

 

[Mark Fergerson]

Duane C. Johnson wrote:

(that he approved of W. P. N. Smith's explanation {BTW
thanks William, that's about what I figured}, and added

I chose a BS107 small MOSFET for it's very low gate
voltage. There are better MOSFETs but that's the one I had.

OK.

The LEDs don't do regulation as there is 10K in series
with them.

I use them as a bootstrap power source to get the
oscillator supply voltage over about .9V. The oscillator
I have here is about the lowest VCC I can get to run
without using germanium transistors.

I've been parting out old handheld CB radios; plenty of
Ge transistors. But I think the IC takes up less space,
those cans are huge. ;&gt

Anyway once the voltage gets to .9V or so the oscillator
starts and Q1 converts power from the PV cell to something
over about 2.5V where the large power MOSFET takes over.

So the green LEDs' Vout droops a bit; but VCC stays high
enough that the gates in U1 can oscillate; that's what I
thought.

Q2, T1, D3 provide a step-up with a transformer boost
to charge the battery. D2 provides overcharge protection
and bootstraps U1.


Yep, crude but effective.

IIRC in the older version there was no transformer, just
a boost coil like L1; but in the newer one you seem to have
it connected as sort of a hybrid balun/autotransformer
thingie. BTW it's a standard small audio type, yes?

Anyway my confusion was how the thing started. I forgot
there'd be _some_ voltage on the NiCd. Silly me.

The two LEDs can apparently also provide some bootstrap
via their PV action.

Yes, a few uA of charge current.
The green LEDs I use have the capability of generating
1.7V. However the the oscillator consumes this current
so I put 2 LEDs in series to get some improvement in
starting time.

I have plenty, I could just stack them up...

and the limited lifetime of standard Si PV cells


Decades aren't enough?

Nope, I'm thinking about an application similar to Watt
Sun's "forever flashers", but I want to charge a supercap
instead of a NiCd, which is why I mentioned stacked green LEDs.

Next question is how many red LEDs I'll need to equal the
Iout of a small PV cell.

Mark L. Fergerson

 

[William P.N. Smith]

Mark Fergerson <mfergerson1@cox.net> wrote:

Anyway my confusion was how the thing started. I forgot
there'd be _some_ voltage on the NiCd. Silly me.

Even if there's no bootstrap from the NiCad, there's apparently enough
bootstrap from the green LEDs to get things going.

Decades aren't enough?

Nope, I'm thinking about an application similar to Watt
Sun's "forever flashers", but I want to charge a supercap
instead of a NiCd, which is why I mentioned stacked green LEDs.

I'm designing some marine navigation beacons using LumiLEDs, and am
currently looking at Hawker Cyclon batteries with a possible solar
charge. How do you calculate the "amp-hours" or discharge
current/voltage profile for a supercap?

Thanks!

--
William Smith wpns@compusmiths.com N1JBJ@amsat.org
ComputerSmiths Consulting, Inc. www.compusmiths.com

 

[Peter Jetson]

Mark van der Eynden wrote:

The Silicon Chip Editorial for September has some comments about
aus.electronics and aus.hifi that could not be described as 'kind'.

Whilst I agree with much of what Leo has to say I do not agree with
his right to say it (Especially as an editorial in SC).

You don't agree with his right to say it? What a strange reaction.

Anyway, everyone here knows who he's talking about. I got a bit of a
laugh from the editorial.

Peter

 

[Mike Harding]

On 27 Aug 2003 15:35:41 -0700, mvandere@iprimus.com.au (Mark van der
Eynden) wrote:

The Silicon Chip Editorial for September has some comments about
aus.electronics and aus.hifi that could not be described as 'kind'.

Whilst I agree with much of what Leo has to say I do not agree with
his right to say it (Especially as an editorial in SC).

One of THE major rules of Usenet, as I understand it, is "If you don't
contribute, you can't criticise".

I presume the opposite is also true and this is perhaps why the most
unkind posts here also come from the people who make the most helpful
posts.

So Leo, come on down, stop lurking and contribute! And please some
contributions from other SC staff as well, take note from EPE staff
who contribute to their forum.

Is it available on a web site? Or do I have to stand in
the newsagents and read it - damned if I'll buy it.

Perhaps Leo (who will, no doubt, be reading) would
have the balls to post it directly to the newsgroups
he, apparently, criticises. Or perhaps he's uncomfortable
with responses he can't edit before they are published?

The newsgroups must be a rather frightening place
to magazine, newspaper and talkback people, normally
they have full control over what the plebs say (hell they
often just change it to suit their agenda!) but on the
newsgroups anarchy rules and they don't have their
ivory towers to hide in - hell we can even defame them
form an anonymous account if we wish too. No wonder
they're scared to enter this particular den.

Mike Harding

 

[Rod Speed]

Mark van der Eynden <mvandere@iprimus.com.au> wrote in message news:48ed3358.0308271435.496a7003@posting.google.com...

The Silicon Chip Editorial for September has some comments about
aus.electronics and aus.hifi that could not be described as 'kind'.

Not very surprising given that quite a few have put the boot into
him and his practices rather enthusiastically in both at times.

Whilst I agree with much of what Leo has to say I do not
agree with his right to say it (Especially as an editorial in SC).

He has the perfect right to say anything he likes, anywhere he likes.

One of THE major rules of Usenet, as I understand
it, is "If you don't contribute, you can't criticise".

No such 'rule'

And usenet is as close as you will ever see to complete
anarchy, there are NEVER any 'rules' anyway.

I presume the opposite is also true

It isnt.

and this is perhaps why the most unkind posts here also
come from the people who make the most helpful posts.

Thats mostly just a result of a basic approach.

And not restricted to usenet either, its true in spades
with very small business. You do tend to get some
pretty gung ho characters involved that dont take
much to trigger into a full 3 deck broadside when they
feel like it, who do know what they are about as well
and who will go out of their way to help you as long
as you dont manage to rub them up the wrong way.

Kids often manage to do that accidentally with
stuff as trivial as starting the email with Hey |-)

So Leo, come on down, stop lurking and contribute!

I dont recall he has ever done anything more than
snipe from the editorial page, over decades now.

His choice.

And please some contributions from other SC staff as well,

There has been one who does.

Tho he mostly just bullshits, particularly
on SCs available in pdf format on CD.

take note from EPE staff who contribute to their forum.

And as someone once said 'If we get more quality
posters, the noise makers will fade to insignificance

That never happens.

(be it a better SN ratio)'

Or that.

P.S. this did not get cross posted to aus.hifi as the
news reader I am using at the moment is not up to it.

Easily fixed.

 

[Mainlander]

In article <MPG.19b6bf5cbcf0831398968a@news.swiftdsl.com.au>,
Phil.dot.Pierotti@SoftHome.dot.NET says...

Tune for minimum smoke?

Also, one last question - so far I've been unable to source even a naked
transformer which produces exactly 9VAC@1.5A output.

So I'm wondering which way I should lean?

Exactly the correct output voltage but higher AMPs (and assume the
internal electronics will only draw what's needed), or vice-versa?

There is no problem at all with using a transformer with a higher current
output as your device will only draw the current it needs. Only voltage
needs to be matched.

On the other hand if the transformer had a lower current rating you could
overload it causing it to be damaged.

 

[Rob]

<wozza@not.home.now> wrote in message news:3F4C793E.8FE24FF9@not.home.now...

Rob wrote:

Guys, can anyone point me in the direction of an Australian supplier of
small (M3/4/5) screws and nuts with integral captive washers.

TIA

Try

Universal Fasteners
60 Grand Junction Rd 5084
Kilburn
Ph: (08) 8300 8700
Fax: (08) 8300 8777

--

David

Thanks David much appreciated, for something so simple its a pain to track
down a good source.
Regards
rob