Driver to drive?

[Paul Burridge]

On 25 Nov 2004 12:51:57 -0800, "lemonjuice" <exskimos@anonymous.to>
wrote:

Oh Yes ... certainly even piezoelectric materials like quartz,
lithium niobate, and lead-zirconate-lead-titanate when strained
generate current.

*Much* more voltage than current, though!

--

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

 

[john jardine]

"Sean Bartholomew" <adrian@rivaband.com> wrote in message
news:b8a337c3.0411251603.5720e547@posting.google.com...

ok im liking this. both possibilities intrigue me,
1st, ur saying that BECAUSE its a wall wart transformer, it IS
floating. i didnt think of that. there is no direct connection to true
ground. nice. so i assign anything i want to ground and connecting
that to outside ground from other devices is fine. ok. ill definitely
try that.

2nd, this 7660 chip INVERTS power? interesting. i was looking at the
MAXIM chip that delivers +-9V from a single 9V supply but all audio
experts inform me that its too noisy for audio usage.
is this 7660 chip noisy? or would it introduce noise in the 5V reg
supply?
[clip]

Yes, like the Maxim chip, the 7660 can be a bit noisy. Though a lot depends
on how much care is taken with cleaning the supply rails.
For simplicity it's easier to go the linear route.
regards
john

 

[Sean Bartholomew]

also a thought just occured to me.
theoretically, if i build TWO regulated 5V supplies from a single 9V
transformer supply, i should be able to connect the positive of one to
the negative (0) of the other treating THAT as ground ref. then id
have +5V, 0 and -5V.

but wouldnt that:
A- simply just short out the ground and the +5V of one of the supplies
since both their grounds are connected?
B- theoretically give me 10V diff total WITHOUT any reclocking from a
9V supply?

 

[john jardine]

"Sean Bartholomew" <adrian@rivaband.com> wrote in message
news:b8a337c3.0411251845.71102f4b@posting.google.com...

also a thought just occured to me.
theoretically, if i build TWO regulated 5V supplies from a single 9V
transformer supply, i should be able to connect the positive of one to
the negative (0) of the other treating THAT as ground ref. then id
have +5V, 0 and -5V.

but wouldnt that:
A- simply just short out the ground and the +5V of one of the supplies
since both their grounds are connected?
B- theoretically give me 10V diff total WITHOUT any reclocking from a
9V supply?

Yes. They can be stacked like that but you'll then need at least a 12V-14V
input as the voltages are now sitting on top of each other.

Unfortunately an awkward problem pops up when stacking positive voltage
regulators.
They can only source current and not sink it. That opamp powered from across
the outer +/-5V rails is fine. The "0V" centre rail is fine.
Trouble comes when the opamp drives to drive a load connected to the "0"V
rail.

When the ouput swing goes below 0V then it's no problem, as current is taken
OUT of the mid rail regulator and passes via the opamp back down the real 0v
line.
But ... when the opamp tries to swing a positive output voltage to its load,
the top regulator is quite happy to feed current via the opamp into the load
but this current then can't go back via the pretend 0V rail into the mid
voltage regulator output pin. Essentially the circuit can only run as a half
wave rectifier.
The inefficient work-around is to stick a resistor across the middle rail
and the bottom rail which constantly passes a current that's a tad more than
the opamp will be liable to ask for when driving its load at maximum. (say
20ma's worth).
regards
john

 

[Michael Black]

Rich Grise (rich@example.net) writes:

On Thu, 25 Nov 2004 15:29:21 -0700, Jim Thompson wrote:

On Mon, 22 Nov 2004 17:49:47 -0700, Jim Thompson
I know this wasn't massively cross-posted, so why am I now reading

this thread in alt.os.linux.slackware?

You had it cross-posted to:

sci.electronics.design
alt.binaries.schematics.electronic
sci.electronics.cad
sci.electronics.misc
alt.os.linux.slackware

This isn't the first time this has happened. Either you are deliberately
throwing in extra newsgroups, such as the slackware one where it most
definitely does not belong, or something in your software is doing it.

Michael

thegreatone@example.com> wrote:

John Woodgate? Haven't heard from him in awhile. Anyone know if he's
OK?

...Jim Thompson

Is anyone paying attention? I sent JW an E-mail and he replied. And
I posted his reply about 6 hours ago. He's fine, just busy.

I am, but didn't think that "Me, too" would contribute much. Glad to hear
he's OK, albeit I hadn't really been all that worried - I am "sending good
energy" to Pat Volkerding, however, who seems to be having some medical
situation, although, lemme see...
http://slackware.osuosl.org/slackware-current/PAT-NEEDS-YOUR-HELP.txt

If you pray or anything, or know somebody who knows somebody medical, this
is a gentleman who appears to actually need some help, and he would be
sorely missed by a community of misfits of which I proudly count myself an
honorary member, Slackers. There's much more on him in
news:alt.os.linux.slackware .

Just sort of had a little urge to post this.

Thanks,
Rich

 

[Sean Bartholomew]

hmmm sounds like i should stick to my original plan then what with the
half wave of stacking 2 5V and the noise of the 7660.
so 9V and 4V here i come. id totally use 10V and 5V but then ill have
to have a supply greater than 12V.

 

[Paul Burridge]

On 26 Nov 2004 01:31:41 -0800, "lemonjuice" <exskimos@anonymous.to>
wrote:

Transistor Circuit design , Mc Graw Hill , By Texas Instruments,
Incorporation written by engineers in the Semiconductors component and
transistor applications division
states in chapter 1 ...that as the the transistor is a current control
device hfe is obviously the most IMPORTANT PARAMETER of a TRANSISTOR.
BTW still have to reply to your earlier post to me .

It would be a *lot* more useful as a parameter if it didn't vary so
much between identical types of devices in practice.
--

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

 

[Paul Burridge]

On Fri, 26 Nov 2004 03:24:37 GMT, Rich The Philosophizer
<null@example.net> wrote:

I think that finding out what it is that they actually _do_ generate will
go a long way towards resolving a lot of other questions. Like, what is
"charge" anyway?

Are you kidding? It's the total amount I have to pay for my
electricity! ;-)
--

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

 

[Don Pearce]

On Fri, 26 Nov 2004 09:36:51 -0500, "Tam/WB2TT"
<t-tammaru@c0mca$t.net> wrote:

"Sean Bartholomew" <adrian@rivaband.com> wrote in message
news:b8a337c3.0411260005.7294917a@posting.google.com...
hmmm sounds like i should stick to my original plan then what with the
half wave of stacking 2 5V and the noise of the 7660.
so 9V and 4V here i come. id totally use 10V and 5V but then ill have
to have a supply greater than 12V.

You guys are still doing it the hard way. If you want +5 and about -5 V from
a 12 V floating supply, connect a 4.7 V zener diode in series with the
negative supply lead, and connect the other end to "ground ". Now connect a
series regulator between ground and the positive supply lead. The original
negative supply lead will be -4.7V. This will work so long as the positive
supply current is more than the negative supply current.

Tam

The way you describe this, it is impossible for the positive and
negative currents to be different, because they are in series with
each other. Also, with a voltage regulator from + to ground, and a
zener from - to ground, there is nothing to limit the zener current,
and it will go pop.

d
Pearce Consulting
http://www.pearce.uk.com

 

[Sean Bartholomew]

thanks for all the help guys. i love this forum.

 

[Ian Stirling]

Winfield Hill <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

http://www.damnsmalllinux.org/

Authored by: gdeinsta on Thursday, November 25 2004 @ 03:02 PM EST

I ordered the business-card sized CD with DSL ("Damn Small Linux").
It arrived a week ago. I put it in the CD drive and... it booted up
perfectly. It's very impressive to watch it go through all the hardware,
poking and prodding to find out what is out there. (It's based on
Knoppix.) The only thing it got wrong was that it didn't adjust to
my two-button mouse, so I have no way of making a "third button" click.

Try clicking both left and right buttons at once.

 

[Ken Smith]

In article <b8a337c3.0411251603.5720e547@posting.google.com>,
Sean Bartholomew <adrian@rivaband.com> wrote:
[...]

2nd, this 7660 chip INVERTS power?

The Intersil 7660 blows up too easily. I suggest the Linear equivelent.
You can get it from digikey.

With both these parts, there cab be a problem if your circuit pulls the
output above ground. Adding a small MOSFET as a common gate stage can
protect it from this.

interesting. i was looking at the
MAXIM chip that delivers +-9V from a single 9V supply but all audio
experts inform me that its too noisy for audio usage.
is this 7660 chip noisy? or would it introduce noise in the 5V reg
supply?

These chips draw their current in spikes. If you RC decouple it from the
+5V, there shouldn't be much trouble with that. You can also add a filter
on the -5V produced.




--
--
kensmith@rahul.net forging knowledge

 

[John Smith]

"Marc H.Popek" <LVMarc@worldnet.att.net> wrote in message
news:M1Ipd.61239$7i4.38104@bgtnsc05-news.ops.worldnet.att.net...

Here are some nice "little" RF transistors.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3855097381&ssPageNam
e=STRK:MESE:IT

FYI: The 2N3866 is available from Mouser for $1.50 ea in small quantities.

 

[N. Thornton]

"Nicholas O. Lindan" <see@sig.com> wrote in message news:<fFqpd.1420$Ua.24@newsread3.news.atl.earthlink.net>...

"Siddhartha Jain" <losttoy2000@yahoo.co.uk> wrote
Nicholas O. Lindan wrote:

At $12.95 you are being ripped off.
This thing is a landfill-liability. You need to be paid for
taking it.

Offer 99 cents for 10 of them. They may take you up on it.

I find the whole thing odd. No-one pays 12.95 for scrap with no use.


NT

 

[Joerg]

Hi Winfield,

Not that I want to sound too critical here but in the old days (early 90's) you could get by with a lot less RAM than the 16MB that they proudly announced after the 'Retro Hardware Party'.

When I ran the Mosaic browser one of my PCs had a mere 4MB of RAM. Another held 8MB and was later upgraded to 16MB. This didn't make a bit of a difference in browser behavior or the behavior of any other software. The only reasons for more memory were large Spice simulations. Also, I often had several other windows open with other apps. I could do the same kind of work that I do today. But today everything needs a gazillion MB and the ritzy Li-Ion battery is sucked dry in under two hours, versus six hours with the ol' NiCads in the 90's.

Oh, and then we did a QNX project at work. The kernel was, I believe, under 40k and the browser was around a megabyte. It handled web pages at the same speed as 'modern' browsers with one subtle difference. It never crashed...


Regards, Joerg

http://www.analogconsultants.com

 

[John Larkin]

On Fri, 26 Nov 2004 22:01:12 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hi Winfield,

Not that I want to sound too critical here but in the old days (early 90's) you could get by with a lot less RAM than the 16MB that they proudly announced after the 'Retro Hardware Party'.

When I ran the Mosaic browser one of my PCs had a mere 4MB of RAM. Another held 8MB and was later upgraded to 16MB. This didn't make a bit of a difference in browser behavior or the behavior of any other software. The only reasons for more memory were large Spice simulations. Also, I often had several other windows open with other apps. I could do the same kind of work that I do today. But today everything needs a gazillion MB and the ritzy Li-Ion battery is sucked dry in under two hours, versus six hours with the ol' NiCads in the 90's.

My Pentium has over 1000x the compute power of my original 4.77 MHz
8-bit PC-XT, and only takes about 15 times as long to boot the OS.

Oh, and then we did a QNX project at work. The kernel was, I believe, under 40k and the browser was around a megabyte. It handled web pages at the same speed as 'modern' browsers with one subtle difference. It never crashed...

I bet it didn't even support jpeg viruses either.

John

 

[Jim Yanik]

Joerg <notthisjoergsch@removethispacbell.net> wrote in
news:IINpd.49830$QJ3.36832@newssvr21.news.prodigy.com:

Hi Winfield,

Not that I want to sound too critical here but in the old days (early
90's) you could get by with a lot less RAM than the 16MB that they
proudly announced after the 'Retro Hardware Party'.

On a side note,it would be nice if you set your news agent to post at or
less than the standard 80 characters width.

--
Jim Yanik
jyanik-at-kua.net

 

[Hal Murray]

that would make a nice set for an inverter to do 12DC to 120 AC

Major power lines switch to DC and then back to AC at the other end.

What sort of parts do they use? Are they listed in catalogs?
Can I purchase them?

--
The suespammers.org mail server is located in California. So are all my
other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited
commercial e-mail to my suespammers.org address or any of my other addresses.
These are my opinions, not necessarily my employer's. I hate spam.

 

[Winfield Hill]

Jim Yanik wrote...

Not that I want to sound too critical here but in the old days
(early 90's) you could get by with a lot less RAM than the 16MB
that they proudly announced after the 'Retro Hardware Party'.

Yes, I remember very well. But those machines didn't support USB,
high-density graphics displays, multitasking, etc., etc.

On a side note, it would be nice if you set your news agent to
post at or less than the standard 80 characters width.

I have no control over my newsgroup posting host, but I generally
manually edit the line length. For example about 70 charactes max
for that post. What happened when you read it? Did I miss a line?


--
Thanks,
- Win

 

[Rolavine]

From: seimens@gmx.ch (Simon Schneiter)

I've designed a circuit using single-rail supply, since the
A/D-converter requires the signal to be between 1V and 4V. I assumed
the peak output voltages of the piezo to be at +10V respectively -10V.

I think your way too high there on your assumption, I've fed Piezo guitar
pickups, both buffered and unbuffered into a mixer board, my guess is between 1
volt and 100 mv max rms output.

I'm a graduate student in electrical engeneering, but not experienced
with anlog stuff.

Wait, how is that possible? And in this case it is just a simple ac coupled
single supply op amp circuit with a gain of about 5, sheesh! What the hell are
they teaching you these days?

Rocky