Marriage is under fire!!

[Walter Harley]

"Paul Burridge" <pb@notthisbit.osiris1.co.uk> wrote in message
news:s3h3j0trjfuv8bhd15kokaolas93u4o5dh@4ax.com...

"Stiff source impedance"? I know what you mean, but have never
encountered that curious term before...

Art of Electronics.

 

[Paul Burridge]

On 30 Aug 2004 22:41:28 GMT, "Walter Harley"
<walterh@cafewalterNOSPAM.com> wrote:

"Paul Burridge" <pb@notthisbit.osiris1.co.uk> wrote in message
news:s3h3j0trjfuv8bhd15kokaolas93u4o5dh@4ax.com...
"Stiff source impedance"? I know what you mean, but have never
encountered that curious term before...

Art of Electronics.

I don't think so... "stiff signal source" might be a better term.

--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[Andrew Gabriel]

In article <877jrgl7gl.fld@barrow.com>,
floyd@barrow.com (Floyd L. Davidson) writes:

andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:
In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
According to US sources, problems such as you report never occur, and
they don't need to implement the IEC versions of those ENs as US
standards. So you are actually just imagining the flicker. (;-)

The irony is this is quite common in the US, but I've never seen
it happening in a 240V country ;-)

Well... obviously the current is halved, but...

And the percentage voltage drop is quartered...

A laser printer that dims the lights???? Jus how common is
that, really?

Also, we don't run fixed lighting from same circuits as power
outlets.

--
Andrew Gabriel

 

[Pooh Bear]

John Woodgate wrote:

According to US sources, problems such as you report never occur, and
they don't need to implement the IEC versions of those ENs as US
standards. So you are actually just imagining the flicker. (;-)

Tssk @ you John.

You're suggesting that the IEC has 'versions' of the ENs ? Other way surely
!


Graham

 

[keith]

On Mon, 30 Aug 2004 18:53:56 +0100, John Woodgate wrote:

I read in sci.electronics.design that John Larkin <jjlarkin@highSNIPland
THIStechPLEASEnology.com> wrote (in <7fo6j05rp857et2n7tbqlp12bavl48qrrv@
4ax.com&gt about 'How to bias a MOSFET amp?', on Mon, 30 Aug 2004:
He said surgeon, not sturgeon.


But, being male, PB is not even a potential source of caviar.

OTOH, he's a good source of other slime. If you want ot go there, be my
guest!

--
Keith

 

[keith]

On Mon, 30 Aug 2004 19:11:01 +0100, Paul Burridge wrote:

On Mon, 30 Aug 2004 18:53:56 +0100, John Woodgate
jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that John Larkin <jjlarkin@highSNIPland
THIStechPLEASEnology.com> wrote (in <7fo6j05rp857et2n7tbqlp12bavl48qrrv@
4ax.com&gt about 'How to bias a MOSFET amp?', on Mon, 30 Aug 2004:
He said surgeon, not sturgeon.


But, being male, PB is not even a potential source of caviar.

Hey ladies, gimme a break will ya? Don't make your PMS my problem. ;-)

Paul's Miserable Shit?

--
Keith

 

[Louis Bybee]

<phil-news-nospam@ipal.net> wrote in message
news:cgvv6622lj3@news1.newsguy.com...

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk
wrote:

| In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
| John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|> According to US sources, problems such as you report never occur, and
|> they don't need to implement the IEC versions of those ENs as US
|> standards. So you are actually just imagining the flicker. (;-)
|
| The irony is this is quite common in the US, but I've never seen
| it happening in a 240V country ;-)

We do have 240 volts. The problem is that we also have the NFPA that
publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
and plug equipment to a maximum of 120 volts relative to ground, thus
disallowing the use of the 240 volt connection for the typical laser
printer. Of course one might get around this if they say it is a 26A
load instead of a 8A (relative to 120 volts).

I guess I should put this in the "favorite beef with the NEC" thread.

I don't know that this would affect it all that much, but I've also
heard that in UK, available fault current at homes tends to be higher
than in the US (one transformer serving a whole block of homes instead
of the typical 1 to 4 in the US). I'm not sure I'd really like having
higher available fault current.

--
--------------------------------------------------------------------------
---
| Phil Howard KA9WGN |

210.6(A) applies to dwelling and guest rooms of hotels, motels, etc. This
article wouldn't be applicable to homes, and office environments. It also
relates to voltage between conductors. Ground isn't referenced in 210.6(A).

210.6(A)(2) restricts to 1,440 va and below, or 12 amps at 120 volts again
in dwelling and guest rooms of hotels, motels, etc.

As you alluded there may well be Laser Printers that would qualify to be
used in dwelling and guest rooms of hotels, motels, etc. at 240 volts due to
being rated in excess of the above limitations. However, most I've seen for
use in USA are rated at 120 volts.

210.6(C) would allow the Laser Printers to be utilized at 240 volts in
dwellings, offices, etc. Again most consumer Laser Printers are sold in a
120 volt configuration.

Most 240 volt circuits, in areas of the USA that I'm familiar with, are 120
volts with respect to ground with the exception of the wild leg of a 240
volt 3 phase delta, with one leg center tapped to ground. In that case the
wild leg usually isn't present in panels designed for single phase loads.

The voltage drop/lights blinking issue that the OP brought up is for the
most part related to older style Laser Printers, and in many cases is
usually associated with circuits that are likely in trouble without the
addition of the printer. I have also seen older Laser Printers that had much
worse numbers than reported by the OP.

When confronted with such a condition I usually recommend a newer printer,
and/or an electrician to install a new circuit, or break up the existing
load between circuits to provide as light a load as possible on the printer
circuit.

It absolutely boggles my mind to see the spendy installations undertaken
without the design services of an engineer, or knowledgeable electrician
before the installation commences.

Never enough time or money to do it right the first time, but always enough
after the fact! :-]

Louis--
*********************************************
Remove the two fish in address to respond

 

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:
| In article <877jrgl7gl.fld@barrow.com>,
| floyd@barrow.com (Floyd L. Davidson) writes:
|> andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:
|>>In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
|>> John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|>>> According to US sources, problems such as you report never occur, and
|>>> they don't need to implement the IEC versions of those ENs as US
|>>> standards. So you are actually just imagining the flicker. (;-)
|>>
|>>The irony is this is quite common in the US, but I've never seen
|>>it happening in a 240V country ;-)
|>
|> Well... obviously the current is halved, but...
|
| And the percentage voltage drop is quartered...
|
|> A laser printer that dims the lights???? Jus how common is
|> that, really?
|
| Also, we don't run fixed lighting from same circuits as power
| outlets.

Now days, most homes here have lighting split from outlets. I have to
remember way way back to where they were shared.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

[Michael A. Covington]

"Alex Bryant" <alex1138@charter.net> wrote in message
news:4b12f51d.0408310633.3880ed0f@posting.google.com...

I have a series of mini-bulbs (#44 lamps, like the kind used in
pinball machines) underneath a platform in my project. My
microcontroller hits various transistors in order to get the 6 volts
to the appropriate lamp. Everything works, but the lamps that are
farthest away from the power source get their current from small wires
about 6 feet long, and hardly glow at all. I need all these lamps to
glow their brightest, to be seen through a series of clear plastics.
Because of the way I've built this whole thing, I can't get the power
source (4 AA batteries) much closer to the bulbs. Would thicker wire
be the answer?

How thin is the wire? I think you have something else wrong.

The resistance of a #44 lamp, when illuminated, is about 25 ohms. Your wire
would have to be microscopically thin to have a resistance comparable to
that in a 6-foot run. Check voltages at both ends.

 

[bushbadee]

That is also a problem with tv sets.
When the power first comes on the cold filimants draw a large surge.
What you can do is soldeir a surgistor in line with the device that heats
the drum.
When you turn it on at first the surgistor has a high impedance and as it
warms up it resistance drops to a low value. This reduces or eliminates the
inrush current (Also some times seen on large transformers)
There are also surgistors that have built in points that close when the
device heats up so there is no voltage across the device. When the power
shuts off, the points open up to be ready for the next surge.

If you have an oscilliscope, I am assuming you would know how to do this.





"~Dude17~" <dude17@sacbeemail.com> wrote in message
news:b959931f.0408290758.2592a92d@posting.google.com...

X-No-Archive: Yes

I've got a laser printer that draws current in spikes and it
makes the lights flicker as well as causing a UPS on the same circuit
to switch over to battery due to excessive dV/dT. Unfortunately, I
don't have a way of putting the printer on its own circuit unless I
want to use a long extension cord.

When it's in sleep state, it draws about 0.22A. When I print
something, it draws about 8A RMS to heat up. After it's done
printing, it stays in "ready to print" state for about ten minutes
before going to sleep and this is where problem starts.

Had the printer for a while, but I finally bothered to check it out on
scope.

I captured the event on my storage oscilloscope and this is what I
found:

At the start of cycle it draws 26A RMS for about 32mS or two cycles
and tapers down to 8.5A RMS after 550mS. Between the start and 550mS,
there's two spikes of about 8mS where current is only drawn from half
of the cycle. After 550mS, the current draw drops to 0.22A RMS, then
starts this whole cycle again after 15 seconds.

If you're a visual type of person, here's the actual capture:
http://dude17site.tripod.com/printer.html

Is there a reason it needs to draw current in this pattern instead of
spreading it out over a longer period of time?

 

[John Woodgate]

I read in sci.electronics.design that phil-news-nospam@ipal.net wrote
(in <ch1hbq226nh@news2.newsguy.com&gt about 'Laser printer draws current
in a spike, what for?', on Tue, 31 Aug 2004:

I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had 60
amp service, it could work.

Experience shows that there is a huge allowance that can be made for
diversity. The average consumption of a UK house is 1 kW. I believe it's
3 kW in USA. You can tell from your bills. So 12 houses at 3 kW is 36
kW. A 75 kVA transformer would be quite OK, unless some exceptional
condition arose. I have put on 7 kW of fan heaters in my house when I
returned to find that the boiler was not working. If everybody did
that....
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Jim Thompson]

On Tue, 31 Aug 2004 22:59:37 +0100, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that phil-news-nospam@ipal.net wrote
(in <ch1hbq226nh@news2.newsguy.com&gt about 'Laser printer draws current
in a spike, what for?', on Tue, 31 Aug 2004:

I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had 60
amp service, it could work.

Experience shows that there is a huge allowance that can be made for
diversity. The average consumption of a UK house is 1 kW. I believe it's
3 kW in USA. You can tell from your bills. So 12 houses at 3 kW is 36
kW. A 75 kVA transformer would be quite OK, unless some exceptional
condition arose. I have put on 7 kW of fan heaters in my house when I
returned to find that the boiler was not working. If everybody did
that....

My monthly average for July was 8.1kW, so I probably had peaks 2X-3X
as much.

...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.

 

[Michael A. Covington]

I'm not familiar with expos of this type, but you might enjoy hamfests,
which are basically swap meets for ham radio enthusiasts. www.arrl.org has
a list of them.

"Donald J. Bartley" <djbcoffee@sbcglobal.net> wrote in message
news:192f38ee.0408311226.69298d10@posting.google.com...

I have been searching the web looking for any events for electronics
hobbyists. A show/expo that showcases the latest in gadets for
robotics, electronics, stamp modules, microcontrollers, acceossies,
etc. Does anybody know of any such shows/expos or where to go on the
web to find this information.

Thanks!

 

[Active8]

On 31 Aug 2004 16:47:18 -0700, PuMonchu2005 wrote:

Hey folks, this is my first post.
I want to get degrees in EE and Computer Engineering, but now I would
like some practice.
I have 3 spare hard drives laying around (2 3GB and 1 6GB) and a
couple video cards. I was wondering if there was anything I could do
with these things? Anything really. I was thinking of just taking them
apart or something, but that wouldn't learn me anything.
If anyone could post some links to a site that has projects to do with
spare comp parts, that would be awesome.
Thanks

What I did last week was to go to the recycling center and went
dumpster diving for more spare parts. Brought 'em home, stripped 'em
and took the carcases back. Could have saved a case cover for sheet
metal, but I can always go back. Also could have fixed that 17"
monitor, but I only had room for the one I found that worked

I also got a working tower and a few video and sound cards. THe
compaq POSs worked, too, but being POSs, I just stripped 'em. Of
course I let them boot and read all the dirty sh*t educators don't
remove from their computers before they trash 'em. 1 unit from a
college prof and 2 from some middle school with a bunch of little
supposedly educational games.

So I build a new Linux box. It might be a bit slow for X windows,
have to pare it down and see, but it'll serve up files fast. If that
node hub I grabbed works, I might use it, too.

That's not a bad idea - a linux box. You're likely to benefit from
the Linux experience.

If you don't do as I, I figure the hassle of taking the components
off for parts is just a timely PITA. I can't think of what you might
do with a card other than using it as a spare or putting it in a new
system.

But if nothing else. Look at the way the boards are laid out and how
the tracks are routed. You can take a picture for posting to the
binaries group if you have any specific questions. Just edit the
photo and circle the area of interest. Save as JPG to keep the size
down. Possible PNG but only if it's smaller, which for that kind of
picture, I doubt it will be.

Have fun. Good luck.
--
Best Regards,
Mike

 

[Rich Grise]

Dubs wrote:

You can also use a double run of
smaller gauge wire.


Really? That sounds a lot less costly. Is there a way to have a
double run result in one outlet, or do you just have two?

Thanks
Dub

Run 240 with a neutral, and split the load at the shed.

Cheers!
Rich

 

[John Woodgate]

I read in sci.electronics.design that Jim Thompson
<thegreatone@example.com> wrote (in <vku9j09163udbim9ij740h67ru4243ob22@
4ax.com&gt about 'Laser printer draws current in a spike, what for?', on
Tue, 31 Aug 2004:

My monthly average for July was 8.1kW, so I probably had peaks 2X-3X as
much.

Mostly for egg-nishners?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Stan Blazejewski]

On 29 Aug 2004 21:12:30 GMT, bobgardner@aol.comma (BobGardner) wrote:

Could a solenoid be constructed to mimic
the proper valve position vs time curve of a
engine cam shaft?
===================
http://rbowes1.11net.com/dbowes/

Thats' been done already, they're still ironing out the bugs.... not

ready for domestic use 'yet'.

I must say I just 'love' the possibilities this will introduce.
Imagine an engine that could putt around in city traffic & still go
like a Ferari on the open road.
--

Australia isn't "down under", it's "off to one side"!

stanblaz@netspace.net.au
www.stanblaz.customer.netspace.net.au
www.cobracat.com (home of the Australian Cobra Catamaran)

 

[John Fields]

On 1 Sep 2004 06:11:03 -0700, alex1138@charter.net (Alex Bryant)
wrote:

Well, it's not microscopically thin, but it's close...standard red
Radio Shack project wire. I'm on the road at the moment and can't
check the voltage, but maybe I'm implementing the transistors
wrong...Would the rating of the resistor going to the base of my
transistor, affect how much current goes out the emitter to the lamps?

---
BINGO!

Depending on how much current comes out of your micro's IOs when
they're feeding the base of the transistor, figure the drop across the
base resistor plus about 1.2V and subtract that from the supply
voltage. What's left over will be the voltage into the lamp(s).

What you should do is use the transistor for a low side switch, like
this:
+V
|
[LAMP]
|
C
IO>---[R]---B
E
|
GND

The value of R will depend on the gain of the transistor and how much
current your micro can source, but for a #44, which takes 250 mA at
6.3V and a transistor with a beta of at least 100 with 250mA going
through it, your IO will need to supply 2.5mA, so that's about 2000
ohms. Regardless, you should make sure your transistor goes into
saturation so the power it dissipates (which will be 'stolen' from the
lamp) won't cause excessive dimming. Or, use a logic level MOSFET and
forget about having to worry about base current at all.

The other problem might be that you're wiring your lamps like this:

+6V-----+- - - - - -+
| |
[LAMP 1] [LAMP n
| |
GND-----+- - - - - -+


When, if you're using thin wire, you should be wiring them like this:


+6v-------------------------+
|
+6v------------+ |
| |
+6V--+ | |
| | |
[LAMP 1] [LAMP 2] [LAMP n
| | |
D | |
IO>-G | |
S | |
| | |
GND>-+ | |
D |
IO>-----------G |
S |
| |
GND>-----------+ |
D
IO>------------------------G
S
|
GND>------------------------+
That way, the voltage drop in the wires caused by the current draw of
each lamp will be restricted to its own loop and won't affect the
other lamps.

--
John Fields

 

[peterken]

What thickness of copper was used on the flex board ?
What's the power consumption of the radio-part ?

Possible solutions (one or all):
Use a stranded connection for ground connection between both boards, better
ground connection between both boards
Use extra caps on the power lines on the boards (say 1nF for RF in parallel
with say 47uF for power stability)

Ultimate solution
Revise the layout, putting power-consuming parts closer to power supply
(or power the boards from the side of the most power-consuming end)



"Dummy" <ahkit1021@yahoo.com> wrote in message
news:74bb84c0.0409010237.43c4b745@posting.google.com...
As an attempt to shrink the size of radio, RF and microcontroller
board are separated with a flex PCB, instead of residing on the same
PCB. RF ground is connected to microcontroller ground through the flex
PCB. Besides ground, the are still a number of pins connected from RF
to microcontroller board. Both PCBs share the same 7.5V supply.

Separation of RF board and microcontroller board has caused a problem
which certain amount of distortion was measured from the transmitted
DTMF tone. A check on the radio without RF and microcontroller
separation showed that the distortion level was far lesser, 13% vs 5%.

The distortion disappeared when separate power supply was used for RF
and controller board. Can somebody shed some light on this?

 

[Michael A. Covington]

What is the LED supposed to indicate?