Driver to drive?

[Spehro Pefhany]

On Tue, 20 Aug 2013 06:28:59 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Tuesday, August 20, 2013 1:33:01 AM UTC-4, Spehro Pefhany wrote:
On Mon, 19 Aug 2013 22:32:24 +0100, the renowned Mike Perkins

spam@spam.com> wrote:



On 19/08/2013 18:42, Spehro Pefhany wrote:

On Mon, 19 Aug 2013 09:49:18 -0700, Mike Cook <mcham@NOTyahoo.com

wrote:



http://www.autoshop101.com/forms/alt_bwoh.pdf



has photos of an alternator with 4 connections for windings (each

of 3 phases + common), and the 8 diode rectifier. But wiring

diagrams show only 3 connections and 6 diodes.



Where does the common winding terminal connect (there is a

connection on the rectifier plate)? Where do the other 2 diodes

connect?



The common in the Wye connection (called "Neutral Junction" in the

photo on page 18) goes to the 4th pair of diodes (and typically the

regulator). The other three pairs of winding ends ("Stator Lead

Ends") go to the other three pairs of diodes.





Not the alternators I've taken apart. The star point is typically a

crimp, and serves no other useful purpose.



Those were alternators with only six power rectifiers, right?



The field, and regulator power, are normally taken from an additional set of

diodes, usually 3, ie one per phase, such that the regulator is

effectively isolated from the battery when the engine is not turning.



The power rectifiers connected to the Wye common are used to extract

3rd harmonic power- yielding up to 10% additional current capacity-

when operating at high speed.

Interesting, Thanks! (I assume it's as shown in the link that ed posted earlier.)
http://autonopedia.org/renewable-energy/generators/alternator-secrets/
George H.

Yes, this patent (Fig 2) shows the construction a bit more clearly
(but no explanation of _why_).

http://patentimages.storage.googleapis.com/pdfs/US6528911.pdf

The efficiency of the highly optimized (for cost) automotive Lundell
claw pole generator is apparently only about 50%. That's a lot of
wasted gasoline given the high electrical loads on modern cars (mine
has an electric water pump and electric steering, for example).

 

[Spehro Pefhany]

On Tue, 20 Aug 2013 11:02:55 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Tuesday, August 20, 2013 12:37:31 PM UTC-4, Spehro Pefhany wrote:
On Tue, 20 Aug 2013 06:28:59 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:



On Tuesday, August 20, 2013 1:33:01 AM UTC-4, Spehro Pefhany wrote:

On Mon, 19 Aug 2013 22:32:24 +0100, the renowned Mike Perkins
snip

The power rectifiers connected to the Wye common are used to extract



3rd harmonic power- yielding up to 10% additional current capacity-
when operating at high speed.
Interesting, Thanks! (I assume it's as shown in the link that ed posted earlier.)

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

George H.


Yes, this patent (Fig 2) shows the construction a bit more clearly
(but no explanation of _why_).

Hmm, if there is a lot of current being drawn maybe you 'win' by not having the resistance of the other stators in the current path.



http://patentimages.storage.googleapis.com/pdfs/US6528911.pdf



The efficiency of the highly optimized (for cost) automotive Lundell

claw pole generator is apparently only about 50%. That's a lot of

wasted gasoline given the high electrical loads on modern cars (mine

has an electric water pump and electric steering, for example).

So I'm guessing they optimize for the 'up front' cost of the car and not your cost to run it.

You could also get a few more HP during acceleration if you're not
powering a water pump and a hydraulic steering pump. I don't know if
they actually let off on the alternator during heavy acceleration, but
it would make sense.

My wife has a Toyota minivan in which everything seems to have a motor attached. I expect next they will motorize the opening and closing of the two front doors. I mean, I have to set my coffee cup down in the morning to open the door... that's much to much to ask. :^)

George H.

Some people could use a car with a built-in fridge, microwave, lighted
makeup mirror, maybe trash compactor.

 

[Jim Thompson]

On Tue, 20 Aug 2013 15:38:19 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Tue, 20 Aug 2013 11:02:55 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

On Tuesday, August 20, 2013 12:37:31 PM UTC-4, Spehro Pefhany wrote:
On Tue, 20 Aug 2013 06:28:59 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:



On Tuesday, August 20, 2013 1:33:01 AM UTC-4, Spehro Pefhany wrote:

On Mon, 19 Aug 2013 22:32:24 +0100, the renowned Mike Perkins
snip

The power rectifiers connected to the Wye common are used to extract



3rd harmonic power- yielding up to 10% additional current capacity-
when operating at high speed.
Interesting, Thanks! (I assume it's as shown in the link that ed posted earlier.)

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

George H.


Yes, this patent (Fig 2) shows the construction a bit more clearly
(but no explanation of _why_).

Hmm, if there is a lot of current being drawn maybe you 'win' by not having the resistance of the other stators in the current path.



http://patentimages.storage.googleapis.com/pdfs/US6528911.pdf



The efficiency of the highly optimized (for cost) automotive Lundell

claw pole generator is apparently only about 50%. That's a lot of

wasted gasoline given the high electrical loads on modern cars (mine

has an electric water pump and electric steering, for example).

So I'm guessing they optimize for the 'up front' cost of the car and not your cost to run it.

You could also get a few more HP during acceleration if you're not
powering a water pump and a hydraulic steering pump. I don't know if
they actually let off on the alternator during heavy acceleration, but
it would make sense.


My wife has a Toyota minivan in which everything seems to have a motor attached. I expect next they will motorize the opening and closing of the two front doors. I mean, I have to set my coffee cup down in the morning to open the door... that's much to much to ask. :^)

George H.

Some people could use a car with a built-in fridge, microwave, lighted
makeup mirror, maybe trash compactor.

I'm sure your car has a lighted makeup mirror... mine does. Also
power open and closing the trunk, powered sunscreens, power seats,
heated and cooled seats... on and on and... >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Tue, 20 Aug 2013 16:40:51 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

AD8218_HighSideSense: ADI Model Produces Output Above Rail and Below
Ground

See attachment >:-}

...Jim Thompson

Interesting further FUBAR... ADI's model sort of works correctly at
0Amps with ENB grounded, not perfectly, but close.

Looks like someone got tangled up in their "IF" statements >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[George Herold]

On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:

John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...

On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"

guvbob2003@yahooooooooooooooo.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...

On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"

guvbob2003@yahooooooooooooooo.com> wrote:



Names can be confusing, so here's what I'm doing....



http://img43.imageshack.us/img43/7434/wvm.gif



When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.



Current for both legs is in the 10-50ma range.



A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.



---

For way under $20, this'll work, and if you need NC contacts, all

you'll have to do is put either a solid state relay or a mechanical

relay with a catch diode across the LED.





Thanks John, I'm not following you. Can you sketch the circuit?



---

Sure.



View with a fixed-pitch font like Courier New:





GND->\ <- +12

O-----+----+---+---+------+-----+-------+ +--------NO

| | | | | | | | | O--C

| | | | | [680] |K | O-> \<--NC

|K | | | | | [1N4148] [COIL]- - - -\

[1N4148][7M5][100K]| [10K] [LED] | |

| |Rt | | | |K | |

| | | | | +-----+-------+

| | | | | |

+-----+----|--|-\ | C

| | | >-+----B 2N3904

|Ct +--|+/U1 E Q1

[1ľF] | | |

| [100K]| |

| | | |

GND>--------+----+---+----------+



U1 is any comparator with an input resistance which won't swamp Rt,

and an open-collector output (or an output with a weak pullup to Vcc)

which can sink a few mA without letting Q1 go out of saturation.



So, what's your application?



--

JF





Thanks again! Would this work?



NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20

http://www.alliedelec.com/search/productdetail.aspx?sku=70215850

I was going to say this sounded like a perfect fit for a 555 timer.
(So what's the best RC combo to get 5 seconds from a 555?)

George H.

 

[George Herold]

On Thursday, August 22, 2013 7:20:55 AM UTC-4, John Fields wrote:

On Wed, 21 Aug 2013 18:48:19 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:
On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:
Thanks again! Would this work?
NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
I was going to say this sounded like a perfect fit for a 555 timer.

(So what's the best RC combo to get 5 seconds from a 555?)

George H.



---

T = 1.1RC, so there are an infinite number of combinations available.
The gotcha is that the upper limit of C is going to depend on its
leakage current and the upper limit of R is going to depend on the
leakage of C and the 555's threshold current.

Grin.. sure, that's why I asked. I don't really know 555 timer specs.

So are Jasen's 10 uF and 500k a good choice? (I assume the 10uF could be an Al electrolytic... though I do have big 10uF film caps... spendy.)

George H.

--

JF

 

[George Herold]

On Wednesday, August 14, 2013 10:12:41 PM UTC-4, Phil Allison wrote:

"zed wit"



"TTman"

Any simple way to dump 500Watts fixed @100 volts ? Or is it easier to

have 5 x 100R 100Watt resistors and a big heat sink ? test time would be

1minute...



light bulbs





** Why do so many fools suggest bulbs in place of resistors ??



Incandescent bulbs use tungsten wire that has a strong positive tempco - so

much so that the effective resistance value changes over a ratio of about 12

times from room temp to full brightness.



OTOH, high power resistors use wire that has almost no tempco and the same

goes for heating appliances ( jugs, toasters room heaters etc).

Interesting.. thanks Phil. So do toasters and such use nichrome wire?

I was thinking (erroneously) that since a toaster gets 'red hot', that the resistance of the element would also change a bunch, like tungsten.

I'm going to have to measure a piece... I've got a drawer at home filled with old heating elements.

George H.

... Phil

 

[John Fields]

On Wed, 21 Aug 2013 18:48:19 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:

Thanks again! Would this work?



NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20

http://www.alliedelec.com/search/productdetail.aspx?sku=70215850

I was going to say this sounded like a perfect fit for a 555 timer.
(So what's the best RC combo to get 5 seconds from a 555?)

George H.

---
T = 1.1RC, so there are an infinite number of combinations available.

The gotcha is that the upper limit of C is going to depend on its
leakage current and the upper limit of R is going to depend on the
leakage of C and the 555's threshold current.

--
JF

 

[Jasen Betts]

On 2013-08-13, TTman <pcw1.cad@ntlworld.com> wrote:

Any simple way to dump 500Watts fixed @100 volts ? Or is it easier to have
5 x 100R 100Watt resistors and a big heat sink ? test time would be
1minute...

several metres of nichrome wire, say, a couple of toasters in series

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[George Herold]

On Thursday, August 22, 2013 10:56:06 AM UTC-4, John Fields wrote:

On Thu, 22 Aug 2013 07:36:19 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:





Interesting.. thanks Phil. So do toasters and such use nichrome wire?



---

Yes, though toasters use nichrome "ribbon".

---



I was thinking (erroneously) that since a toaster gets 'red hot', that the resistance of the element would also change a bunch, like tungsten.



I'm going to have to measure a piece... I've got a drawer at home filled with old heating elements.



---

Nichrome has about a tenth the tempco of tungsten:



http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html

Hmm, the numbers for copper and silver look a bit high. I always figure that the temp coef for pure metals should be something like 1/temperature (in degrees K) so something like 0.0033 at 300 K. The numbers on the wiki page look 'better' to me.
http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity
(you've got to scroll down to the table.)

George H.

--

JF

 

[George Herold]

On Thursday, August 22, 2013 11:34:31 AM UTC-4, Phil Allison wrote:

"John Fields"



Nichrome has about a tenth the tempco of tungsten:



http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html



--



** Arrant nonsense.



See table at bottom of this link:



http://en.wikipedia.org/wiki/Nichrome



The actual tempco is slightly non linear and WAAAY less than tungsten or

copper.



Plus 6% at 2000C.
(well F not C... )

But that's pretty neat, it's basically flat from 500 C to 1000 C.
(more fun will be to measure some.)

Tungsten is nearly plus 1200 % at the same temp.







... Phil

 

[George Herold]

On Thursday, August 22, 2013 12:58:59 PM UTC-4, Spehro Pefhany wrote:

On Thu, 22 Aug 2013 05:50:58 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:



On Thursday, August 22, 2013 7:20:55 AM UTC-4, John Fields wrote:

On Wed, 21 Aug 2013 18:48:19 -0700 (PDT), George Herold



gherold@teachspin.com> wrote:

On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:

Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20

http://www.alliedelec.com/search/productdetail.aspx?sku=70215850

I was going to say this sounded like a perfect fit for a 555 timer.



(So what's the best RC combo to get 5 seconds from a 555?)



George H.







---



T = 1.1RC, so there are an infinite number of combinations available..

The gotcha is that the upper limit of C is going to depend on its

leakage current and the upper limit of R is going to depend on the

leakage of C and the 555's threshold current.



Grin.. sure, that's why I asked. I don't really know 555 timer specs.



So are Jasen's 10 uF and 500k a good choice? (I assume the 10uF could be an Al electrolytic... though I do have big 10uF film caps... spendy.)



George H.



They're okay.. depends on the type of 555- CMOS or the old bipolar
type. 5 seconds is short enough that almost anything will work. A low
leakage type electrolytic of 10uF to 100uF would be cheapest in
volume, for one-off, maybe a CMOS 555, a ceramic 1uF with a 5M
resistor but voltage coefficient might come into play. A tantalum 10uF
with 470K should work without problems.



There are two impediments to accuracy with this sort of thing- the
tolerance/leakage of the cap, resistors and chip (mostly the cap) and
how precisely the cap voltage is reset to zero. If, say, 4-6 seconds
delay with a reasonable minimum off time is okay, then you don't need
to worry much about this sort of thing.


In the line of industrial timers I designed a couple careers ago, I
would clamp the cap to within some mV and used a relatively high
voltage for the comparison (about 20V, IIRC) so the accuracy was
excellent even if the reset time was relatively short. They used all

discrete components, the 555 was available but I could see no
advantages at all in using it (I did manage to make a PI temperature
controller for bench top hydraulic presses with a 555 as the only
active component).

If you need more like 1-5% accuracy, the resistor can be trimmed to
compensate for the cap tolerance. If you're building a lot of them, a
microcontroller with either a calibrated RC oscillator (1%-ish
accuracy without adjustment) or a crystal (accuracy probably limited
by the reset circuit) would be better.

Best regards,
Spehro Pefhany

Nice thanks, I've been sorta penciling tantalums out of my design brain. Though I did use a big one ~100uF for a triangle wave thingie years ago.
The one 'gotcha' you left out was a clean voltage reference for the comparator. I semi-screwed up the above triangle wave generator and used the positive supply rail as the reference. There was this little occasional 'hick-up' in the frequency when a 'bang-bang' heater circuit in the same instrument would turn on and drop the positive rail by some ~10's of mV.

George H.

 

[John Fields]

On Thu, 22 Aug 2013 05:50:58 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Thursday, August 22, 2013 7:20:55 AM UTC-4, John Fields wrote:
On Wed, 21 Aug 2013 18:48:19 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:
On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:
Thanks again! Would this work?
NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
I was going to say this sounded like a perfect fit for a 555 timer.

(So what's the best RC combo to get 5 seconds from a 555?)

George H.



---

T = 1.1RC, so there are an infinite number of combinations available.
The gotcha is that the upper limit of C is going to depend on its
leakage current and the upper limit of R is going to depend on the
leakage of C and the 555's threshold current.

Grin.. sure, that's why I asked. I don't really know 555 timer specs.

---
http://www.ti.com/lit/ds/symlink/lm555.pdf
---

>So are Jasen's 10 uF and 500k a good choice?

---
Yeah.
---

>(I assume the 10uF could be an Al electrolytic... though I do have big 10uF film caps... >spendy.)

---
The advantage of film caps over aluminum electrolytics is that leakage
through film caps is close to nothing and they have a much better
tempco.

The low leakage allows a smaller, less expensive capacitor to be used
along with a higher resistance timing resistor.

--
JF

 

[Phil Allison]

"George Herold"
Phil Allison wrote:

"zed wit"

"TTman"

Any simple way to dump 500Watts fixed @100 volts ? Or is it easier to

have 5 x 100R 100Watt resistors and a big heat sink ? test time would
be

1minute...

light bulbs


** Why do so many fools suggest bulbs in place of resistors ??


Incandescent bulbs use tungsten wire that has a strong positive tempco -
so

much so that the effective resistance value changes over a ratio of about
12

times from room temp to full brightness.



OTOH, high power resistors use wire that has almost no tempco and the
same

goes for heating appliances ( jugs, toasters room heaters etc).


Interesting.. thanks Phil. So do toasters and such use nichrome wire?

** Generally - yes.

I was thinking (erroneously) that since a toaster gets 'red hot', that the
resistance of the element would also change a bunch, like tungsten.

** Draw a heap of amps at switch on and blow the fuse - wouldn't it?

Lamps get hot in fraction of a second but heaters do nothing of the sort.

Plus tungsten lamp filaments burn fiercely in air.

I'm going to have to measure a piece... I've got a drawer at home filled
with old heating elements.

** Submersible heating elements may have a small positive tempco - as may
soldering irons.




.... Phil.

 

[John Fields]

On Thu, 22 Aug 2013 07:36:19 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:


>Interesting.. thanks Phil. So do toasters and such use nichrome wire?

---
Yes, though toasters use nichrome "ribbon".
---

I was thinking (erroneously) that since a toaster gets 'red hot', that the resistance of the element would also change a bunch, like tungsten.

I'm going to have to measure a piece... I've got a drawer at home filled with old heating elements.

---
Nichrome has about a tenth the tempco of tungsten:

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html

--
JF

 

[Phil Allison]

"John Fields"

Nichrome has about a tenth the tempco of tungsten:

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html

--

** Arrant nonsense.

See table at bottom of this link:

http://en.wikipedia.org/wiki/Nichrome

The actual tempco is slightly non linear and WAAAY less than tungsten or
copper.

Plus 6% at 2000C.

Tungsten is nearly plus 1200 % at the same temp.



.... Phil

 

[Michael A. Terrell]

Jim Thompson wrote:

On Tue, 20 Aug 2013 16:40:51 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

AD8218_HighSideSense: ADI Model Produces Output Above Rail and Below
Ground

See attachment >:-}

...Jim Thompson

Interesting further FUBAR... ADI's model sort of works correctly at
0Amps with ENB grounded, not perfectly, but close.

Looks like someone got tangled up in their "IF" statements >:-}

Some programmers need a 'Don't bother' instruction.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

[Spehro Pefhany]

On Thu, 22 Aug 2013 05:50:58 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Thursday, August 22, 2013 7:20:55 AM UTC-4, John Fields wrote:
On Wed, 21 Aug 2013 18:48:19 -0700 (PDT), George Herold

gherold@teachspin.com> wrote:
On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:
Thanks again! Would this work?
NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
I was going to say this sounded like a perfect fit for a 555 timer.

(So what's the best RC combo to get 5 seconds from a 555?)

George H.



---

T = 1.1RC, so there are an infinite number of combinations available.
The gotcha is that the upper limit of C is going to depend on its
leakage current and the upper limit of R is going to depend on the
leakage of C and the 555's threshold current.

Grin.. sure, that's why I asked. I don't really know 555 timer specs.

So are Jasen's 10 uF and 500k a good choice? (I assume the 10uF could be an Al electrolytic... though I do have big 10uF film caps... spendy.)

George H.

They're okay.. depends on the type of 555- CMOS or the old bipolar
type. 5 seconds is short enough that almost anything will work. A low
leakage type electrolytic of 10uF to 100uF would be cheapest in
volume, for one-off, maybe a CMOS 555, a ceramic 1uF with a 5M
resistor but voltage coefficient might come into play. A tantalum 10uF
with 470K should work without problems.

There are two impediments to accuracy with this sort of thing- the
tolerance/leakage of the cap, resistors and chip (mostly the cap) and
how precisely the cap voltage is reset to zero. If, say, 4-6 seconds
delay with a reasonable minimum off time is okay, then you don't need
to worry much about this sort of thing.

In the line of industrial timers I designed a couple careers ago, I
would clamp the cap to within some mV and used a relatively high
voltage for the comparison (about 20V, IIRC) so the accuracy was
excellent even if the reset time was relatively short. They used all
discrete components, the 555 was available but I could see no
advantages at all in using it (I did manage to make a PI temperature
controller for bench top hydraulic presses with a 555 as the only
active component).

If you need more like 1-5% accuracy, the resistor can be trimmed to
compensate for the cap tolerance. If you're building a lot of them, a
microcontroller with either a calibrated RC oscillator (1%-ish
accuracy without adjustment) or a crystal (accuracy probably limited
by the reset circuit) would be better.

Best regards,
Spehro Pefhany

 

[Jim Thompson]

On Thu, 22 Aug 2013 12:33:22 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Jim Thompson wrote:

On Tue, 20 Aug 2013 16:40:51 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

AD8218_HighSideSense: ADI Model Produces Output Above Rail and Below
Ground

See attachment >:-}

...Jim Thompson

Interesting further FUBAR... ADI's model sort of works correctly at
0Amps with ENB grounded, not perfectly, but close.

Looks like someone got tangled up in their "IF" statements >:-}


Some programmers need a 'Don't bother' instruction.

Trying to read ADI's model, it looks as if the "designer" got carried
away with nested IF statements and bungled it.

Except for transient response being its own block, I think I can write
down the whole AD8218 behavior as a single EVALUE statement >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Thu, 22 Aug 2013 09:02:44 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Thursday, August 22, 2013 11:34:31 AM UTC-4, Phil Allison wrote:
"John Fields"



Nichrome has about a tenth the tempco of tungsten:



http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html



--



** Arrant nonsense.



See table at bottom of this link:



http://en.wikipedia.org/wiki/Nichrome



The actual tempco is slightly non linear and WAAAY less than tungsten or

copper.



Plus 6% at 2000C.
(well F not C... )

But that's pretty neat, it's basically flat from 500 C to 1000 C.
(more fun will be to measure some.)




Tungsten is nearly plus 1200 % at the same temp.







... Phil

Beware, Nichrome lengthens when hot. Years ago I made a Plexiglas
bender, Nichrome wire in a Bakelite slot so I could get a nice heated
line. Had to use spring-loading to keep the Nichrome from drooping.

...Jim Thompson
--
| James E.Thompson | mens |
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| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.