Anybody producing analog circuits? - Page 2 - Electronic Circuits Projects Diagrams Free

mneary · 22nd April 2009, 11:03 PM

I just sampled three strips of SMD "5%" resistors I have lying around and found mean values of +4.0%, -3.0%, and -0.3%. They had std dev's of 0.2%, 0.2% and 0.1% respectively.

Bobmar7 · 23rd April 2009, 10:51 AM

Dear Mneary,
I believe that you have proven that manufacturers run parts in batches. All of the parts in a single run always have a tight group with a much smaller sigma over mean than the tolerance. However, the run to run tolerance is what really establishes the purchased tolerance.
A smart analog designer would find ways to use parts from a single run or batch and set is gain by series and parallel parts.
Good Job!
Dr. Bob

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar
Title	Starter	Forum	Replies	Latest
Producing a chip with 40 pins	dramrattan	General Electronics Chat	1	9th March 2009 02:01 PM
Alternative means of producing amplification	TheVictim	General Electronics Chat	7	6th June 2007 04:44 AM
producing heat (i.e. car cigarette lighter)	tmp0	General Electronics Chat	12	3rd February 2007 08:23 PM
Designing Analog circuits	gauravbijlani	Micro Controllers	1	15th December 2006 10:12 PM
analog components in digital circuits	oristim	Electronic Projects Design/Ideas/Reviews	11	7th January 2004 08:34 PM

22nd April 2009, 11:03 PM	#16
mneary	I just sampled three strips of SMD "5%" resistors I have lying around and found mean values of +4.0%, -3.0%, and -0.3%. They had std dev's of 0.2%, 0.2% and 0.1% respectively.

23rd April 2009, 10:51 AM	#17
Bobmar7	Dear Mneary, I believe that you have proven that manufacturers run parts in batches. All of the parts in a single run always have a tight group with a much smaller sigma over mean than the tolerance. However, the run to run tolerance is what really establishes the purchased tolerance. A smart analog designer would find ways to use parts from a single run or batch and set is gain by series and parallel parts. Good Job! Dr. Bob