Test Only

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
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Bob Scott
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Test Only

Post by Bob Scott » Mon Mar 03, 2008 5:14 pm

Image

Oh wow. I haven't been posting images because I though that I needed web space in order to link. Uploading works....really well. I can see all the erasures and finger oil smudges that are less visible in the original.
Bob

Dean Huster
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Post by Dean Huster » Mon Mar 03, 2008 7:04 pm

And here I thought that when you did a test, you either went "RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY" or "The quick brown fox jumps over the lazy dog. 0123456789"

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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Bob Scott
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Post by Bob Scott » Mon Mar 03, 2008 8:30 pm

Dean Huster wrote:And here I thought that when you did a test, you either went "RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY" or "The quick brown fox jumps over the lazy dog. 0123456789"
Dean, that's for typewriters. I'm testing the advanced art of drawing with my dwindling supply of surplus ancient IBM Electrographic pencils originally used for filling in optical card data.

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Dave Dixon
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Post by Dave Dixon » Tue Mar 04, 2008 5:02 am

Just came across this yesterday. I hope it isn't too far off topic!
Introducing the new Bio-Optic Organized Knowledge device, trade-named BOOK.
BOOK is a revolutionary breakthrough in technology; no wires, no
electric circuits, no batteries, nothing to be connected or switched on. It is so easy to use, even a child can operate it. Compact and portable, it can be used anywhere – even sitting in an armchair by the fire – yet it is powerful enough to hold as much information as a CD-ROM disc.
Here’s how it works:

BOOK is constructed of sequentially numbered sheets of paper
(recyclable), each capable of holding thousands of bits of information. The pages are locked together with a custom-fit device called a binder which keeps the sheets in their correct sequence.
Opaque Paper Technology (OPT) allows manufacturers to use both sides
of the sheet, doubling the information density and cutting costs.
Experts are divided on the prospects for further increases in
information density; for now, BOOKS with more information simply use more pages.
Each sheet is scanned optically, registering information directly
into your brain. A flick of the finger takes you to the next sheet.
BOOK may be taken up at any time and used merely by opening it.
BOOK never crashes or requires rebooting, though like other display devices it can become unusable if dropped overboard. The ‘browse’ feature allows you to move instantly to any sheet and move forward or backward as you wish.

Many come with an ‘index’ feature, which pinpoints the exact location of any selected information for instant retrieval.
An optional "BOOKmark" accessory allows you to open BOOK to the exact place you left it in a previous session, even if the BOOK has been closed.
BOOKmarks fit universal design standards; thus, a single BOOKmark can be used in BOOKs by various manufacturers. Conversely, numerous BOOK markers can be used in a single BOOK, if the user wants to store numerous views at once. The number is only limited by the number of sheets in the BOOK.
Personal notes next to BOOK text entries can be made with an optional programming tool, the Portable Erasable Nib Cryptic Intercommunication Language Stylus (PENCILS).
Portable, durable, affordable, BOOK is being hailed as a precursor of
a new entertainment wave.
BOOKs appeal seems so certain that thousands of content creators have committed to the platform and investors are reportedly flocking to invest. Look for a flood of new titles soon.

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philba
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Post by philba » Tue Mar 04, 2008 8:17 am

when I click on the image, I don't get a larger view. just a text page with some URLs on it. Not sure who or what is broken.

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Post by gerty » Tue Mar 04, 2008 8:49 am

If you give it a minute it should come up, at least it did for me....

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Post by Dean Huster » Wed Mar 05, 2008 6:20 am

Yeah, it comes right up for me, no problem, although I noticed that all the device type numbers and pin numbers seemed to drop out on the enlarged view. :)

Bob, typewriters, no. Teletypes, yes. The "Fox" message was a standard test message output by TTY generators. The "RYRYRY" typed into a TTY system generates a square wave output signal, a nice, symmetrical signal that's easy to check with a scope.

Dave, I much prefer the new BOOK system over all the others available. In fact, I very, very rarely go on-line for any IC or solid state device data, but instead consult one of maybe 100+ volumes of dataBOOKs, which contain the data in graphical, tabular, textual and photographic form. Fabulous! It is my main form of entertainment input as several fiction authors have committed to using the BOOK system over publishing their writings as on-line text.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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Dave Dixon
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Post by Dave Dixon » Wed Mar 05, 2008 6:51 am

I totally agree with you Dean. I have a closetful of databooks here at work, and am rarely seen during lunchtime without my nose in a good fictional book to take me away from reality for a short time. I've considered a portable ebook reader, but am still not happy with the (lack of) features. The first ones out didn't even have any sort of index! What else are computers made for, if not to make data easily retrievable? I think I'll be sticking with these BOOK things for a long time. Regards, Dave

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Post by haklesup » Wed Mar 05, 2008 11:24 am

I think a killer app would be an eBook reader with text to speech and selectable voices*. Do you think avid readers would embrace this or is it really the reading that makes it all enjoyable. Just testing my thoughts.

*Assuming they are suitably natural sounding, who wants to listen to Stephen Hawking read Stephen King. Similar TTS technology is being used in the car navigation GPS and takes only 1 or 2MB of code though the voices are still a bit gravelly.

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MrAl
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Post by MrAl » Wed Mar 05, 2008 12:19 pm

Hi Bob,

I see you are testing the four MOSFETs, to see how long they can
live with a big spike of current going through them every time
the drive wave changes state because that's what happens when
there is no dead time between states. Let me know...
LEDs vs Bulbs, LEDs are winning.

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Bob Scott
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Post by Bob Scott » Wed Mar 05, 2008 9:06 pm

MrAl wrote:I see you are testing the four MOSFETs, to see how long they can live with a big spike of current going through them every time
the drive wave changes state because that's what happens when
there is no dead time between states. Let me know...
Oh, not concerned about current spikes. I have a whole bunch of Godzilla 0.003 Ohm IRF3713s left over from a CPU liquid cooling thermal servo prototype development project. Most (all?) power MOSFETs have the intrinsic body diode on the substrate to limit flyback voltage, and the maximum flyback current will not exceed the normal drive current. Any cheap old IRFZ44 ought to do but I just don't like using heat sinks.

[edit] Oh, wait. I see what you mean Al. You mean all that Drain-Gate capacitance will slow down turn-off. Ah-Ha! something to play with.[/edit]

Dean, all the ICs are 4000B series running at 12V. How many dual D FFs and XNOR gates are there in 4000B CMOS?

BTW, the analog controlled stepper motor speed controller design isn't finished yet. I think I'll have to raise both oscillator frequencies and I still have to flesh out the VCO. I can't use the VCO from a 4046. Vdd on that IC is 5V max.

I could post the circuit description of the schematic if anybody is interested.

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Bob Scott
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Post by Bob Scott » Wed Mar 05, 2008 11:51 pm

Dave Dixon wrote: I hope it isn't too far off topic!

Personal notes next to BOOK text entries can be made with an optional programming tool, the Portable Erasable Nib Cryptic Intercommunication Language Stylus (PENCILS).
Yes, PENCIL is the original What You See Is What You Get Graphical User Interface. No anti-aliasing software is required. Has a working life longer than most cellphones.

Taken with 4 ounces of milk, pencil is a good dietary source of calcium and protien.
PENCIL: 100% fat free!

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MrAl
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Post by MrAl » Thu Mar 06, 2008 2:28 am

Hi Bob,

I was talking about the current spike due to the MOSFET having
slower turnoff time than turn on time. That is, there is a short
time period where both the upper and lower MOSFET is turned
on at the same time. When say the lower is turned on and the
upper is off, then the drive state changes, then the upper turns
on while the lower is still on, then the lower finally turns off.
During the time they are both on a larger than normal current
spike appears through both MOSFETs.
In most switching supplies there is a 'dead time' built in to
prevent the drive signal from turning on a MOSFET while another
one is on. It's usually implemented as a simple asymetrical delay,
where the turn off drive is not delayed but the turn on drive is.
This is actually built in to several switching regulator control ic's
and the delay is sometimes programmable.

Im not familiar with the IRF3713 but i would guess it's got a hefty
200A or so IDS rating? That might help keep it alive too :smile:
LEDs vs Bulbs, LEDs are winning.

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Bob Scott
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Post by Bob Scott » Thu Mar 06, 2008 7:24 am

MrAl wrote:Hi Bob,

In most switching supplies there is a 'dead time' built in to
prevent the drive signal from turning on a MOSFET while another
one is on.
Mr Al. Yes I have a patent on a DC-DC converter where I built in a 1% dead time to prevent shoot-through through the H bridges. I used IRFZ44 N channe land IRF5305 P channel MOSFETs for that project. It was way overbuilt for a new company that absolutely positively required a bullet proof circuit for company survival.

If I were to add dead time to this circuit, I would add and logic gates to the FET drivers that would sense for low FET gate voltage before allowing the other FET to turn on.
MrAl wrote:Im not familiar with the IRF3713 but i would guess it's got a hefty 200A or so IDS rating? That might help keep it alive too :smile:
Yes, my most important criteria for selecting a power MOSFET is the Rds(on). One with resistance low enough so that I don't need the added expense of heat sinks usually comes with a humungous current and power rating. The saving on heat sinks and labour fiddling with screws and thermal compound makes up for the high price of the FET.

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Post by MrAl » Thu Mar 06, 2008 11:57 am

Hi Bob,

Ok that sounds good. I just was mentioning this in case you didnt
know about what could happen with no dead time. Since you are
aware of this that's taken care of already.

I did several circuits like that one already and looked at the current
spike and wow it can go high, so i like people to know about this.
The transistors will stay cooler too with some dead time built in,
and less EMF and noise on the power supply lines to screw up logic
states.
LEDs vs Bulbs, LEDs are winning.

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