Henry Kiefer wrote:


To come back to your question: Spice will give you better results than your
real circuit!

Worked much DX with Spice, have you?

IMHO if the results from spice differ from the
real results then spice is wrong.

BTW have you got a realistic model for the
self-capacitance of an inductor? Can you
predict the self resonance within 5%?


vy 73

Andy, M1EBV

Andy Cowley wrote:
. . .
IMHO if the results from spice differ from the
real results then spice is wrong.
. . .

If the results from SPICE differ from the real results, then your model
is inadequate.

Roy Lewallen, W7EL

Spice is as good as the input is!
Spice is not a Maxwell field equations solver!

You can predict within 5% without Spice?? How?

- Henry

"Andy Cowley" schrieb im Newsbeitrag
...
Henry Kiefer wrote:


To come back to your question: Spice will give you better results than
your
real circuit!

Worked much DX with Spice, have you?

IMHO if the results from spice differ from the
real results then spice is wrong.

BTW have you got a realistic model for the
self-capacitance of an inductor? Can you
predict the self resonance within 5%?


vy 73

Andy, M1EBV

On Mon, 5 Dec 2005 23:53:38 +0100, "Henry Kiefer"
wrote:

Spice is as good as the input is!
Spice is not a Maxwell field equations solver!

You can predict within 5% without Spice?? How?

- Henry

[snip]

Some of us have done better than 5% prediction BC (before CAD)... like
for close to 20 years before I ever saw a computer... and 25 years
before simulation software.

...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.

Sure Jim. I understand you. That was the time where time was cheaper. Once I
programmed a Gauss linear equations system solver on my Casio FX-602P -
having 512 bytes and even left one byte (for extensions ;-) It was with
minimal input help system (Showing the indices to input) and the matrix was
of dynamical order. (Sorry for my bad english)

I can buy resistors and capacitors with 5%, sometimes with 1%. If you build
a rc oscillator with 1% component values, you get an error typical 1,5%. And
then you add the active components with horrible semiconductor strayung
values. Of course, it is possible with feedback structures to linearize and
stabilize such systems.
So, where is the difference between measurement of the component values and
calculating by hand the circuit OR setting the measured values in the Spice
component dialog boxes? The difference is the time needed and the
possibility to make errors.

5% is a real good value for an analog system.

Hey Jim - Why you don't answer my second private message? :-(

- Henry


"Jim Thompson" schrieb im
Newsbeitrag ...
On Mon, 5 Dec 2005 23:53:38 +0100, "Henry Kiefer"
wrote:

Spice is as good as the input is!
Spice is not a Maxwell field equations solver!

You can predict within 5% without Spice?? How?

- Henry

[snip]

Some of us have done better than 5% prediction BC (before CAD)... like
for close to 20 years before I ever saw a computer... and 25 years
before simulation software.

...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.

Henry Kiefer wrote...

I can buy resistors and capacitors with 5%, sometimes with 1%.
If you build a RC oscillator with 1% component values, you get
an error typical 1,5%.

I have a nice line of 2% caps in stock, but where do you
get the elusive (affordable) 1% capacitors?


--
Thanks,
- Win

On Wed, 07 Dec 2005 16:05:19 -0800, Winfield Hill wrote:

Henry Kiefer wrote...

I can buy resistors and capacitors with 5%, sometimes with 1%. If you
build a RC oscillator with 1% component values, you get an error typical
1,5%.

I have a nice line of 2% caps in stock, but where do you get the elusive
(affordable) 1% capacitors?

You have undergrads select them. :-)

Cheers!
Rich

OR two capacitors in parallel. The support cap has a nominal value of 1/100
of the bigger cap. So you can tune the bigger.

- Henry


"Rich Grise" schrieb im Newsbeitrag
news
On Wed, 07 Dec 2005 16:05:19 -0800, Winfield Hill wrote:

Henry Kiefer wrote...

I can buy resistors and capacitors with 5%, sometimes with 1%. If you
build a RC oscillator with 1% component values, you get an error
typical
1,5%.

I have a nice line of 2% caps in stock, but where do you get the
elusive
(affordable) 1% capacitors?

You have undergrads select them. :-)

Cheers!
Rich

For example http://www.wima.de/fkp2.htm
But I think there are other manufacturers too.

- Henry


"Winfield Hill" schrieb im Newsbeitrag
...
Henry Kiefer wrote...

I can buy resistors and capacitors with 5%, sometimes with 1%.
If you build a RC oscillator with 1% component values, you get
an error typical 1,5%.

I have a nice line of 2% caps in stock, but where do you
get the elusive (affordable) 1% capacitors?


--
Thanks,
- Win

I have a nice line of 2% caps in stock, but where do you
get the elusive (affordable) 1% capacitors?

Digikey stocks a handful of Panasonic ECQ-P(Z),
POLYPROPYLENE, Radial, 0.001 to 0.47 uF.

Not a great selection, but probably good enough for
many timing applications if you do the fine tuning with
the size of the R.

--
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