The Dirty World of Resistors - Page 1
Forum section: electronics / projects

author: ondreji
author_rank: Contributor
timestamp: August 13, 2014, 06:57:28 am
content: Hi,I had a brief look at Digi-Key SMD resistor selection (around 120 000 SKUs) and here are some insights:Number of manufacturers: 23Top 3 manufacturers: Panasonic Electronic Components, Rohm Semiconductor, Vishay DaleValues: 1015Resistance range (excl. 0Ohm): 0.0002Ohm - 25GOhmTop 10 values*: 10k, 0, 1k, 100k, 100, 4.7k, 10, 1M, 47k, 49..9Top 10 packages*: 0603, 0402, 0805, 1206, 0201, 1210, 2512, 2010, 01005, MELF-0204Top 10 tolerances*: 1%, 5%, 0.1%, 0.5%, 2%, 0.05%, 10%, 0.01%, 0.02%, 0.25%Price (per quantity in AUD):0.02 - 34.30 @ 10.088 - 5.756 @ 102.435 - 22.570 @ 1000.02796 - 8.733 @ 10000.00061 - 0.35630 @ 10000(*) are based on stocked quantitiesResistor QuadrantsAll 23 resistor manufactures can be placed into one of the four quadrants based on:product line uniquenesssingle quantity priceThe four quadrants are:Unique and expensive resistors: Only “Vishay foil resistors” who is famous manufacturer of precision resistors occupies this quadrant.Usual resistor range with special features. Sfernice manufactures MIL spec, aerospace, and medical resistors. Anaren’s speciality is RFYour everyday resistor needs - mass production at low cost. This 10k should be good for pull-up, right?Unique products but the competition keep price down.The manufacturer position might not be correct because the dataset contains Digi-Key stocked product only. For example Digi-Key can stock the majority of values / types / etc from one manufacturer and fill the gaps with cheaper parts from the other manufactures. It would be interesting to see change in manufacturer quadrant position if data from multiple distributors are analysed (Hey, Octopart can I use your data?).The average Joe Resistorlooks like this:Tolerance: 1%Power: between 0.125W and 0.1WComposition: Thick FilmNo special featuresTemperature Coefficient: ±100ppm/CPackage: 0805Enjoy!Edit: this forum doesn't like unicode characters

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 13, 2014, 07:16:41 am
content: Cool!...I still have no idea what to buyTim

author: calmtron
author_rank: Regular Contributor
timestamp: August 13, 2014, 08:13:16 am
content: You gotta love statistics in this business

author: alanambrose
author_rank: Frequent Contributor
timestamp: August 13, 2014, 04:08:48 pm
content: I think this is pretty interesting, and thanks. I just did something similar for capacitor pricing and package size. Just as the assumption that a trace has zero impedance is good a lot of the time ... until it isn't - then, by analogy, assuming a universal resistor population exists i.e. that you can get all resistors in all values at all tolerances at cheap prices works most of the time ... until it falls down badly.Alan

author: dannyf
author_rank: Super Contributor
timestamp: August 13, 2014, 04:12:06 pm
content: QuoteThanks. It is an excellent analysis for the distributors, sourcing departments, management and even engineers - to encourage people to design to / stock those most common parts.

author: c4757p
author_rank: Super Contributor
timestamp: August 13, 2014, 04:13:02 pm
content: Quote from: brevor on August 13, 2014, 07:17:54 amWhat's the point? Why did I waste time reading that? Why did you waste time posting that?

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 13, 2014, 04:33:12 pm
content: Quote from: c4757p on August 13, 2014, 04:13:02 pmIt seems quite probable that brevor didn't get the point of THAT either.Have we lost the concept of "lurking" for a while to get the hang of things before posting?"Better to Remain Silent and Be Thought a Fool than to Speak and Remove All Doubt"

author: amyk
author_rank: Super Contributor
timestamp: August 13, 2014, 08:48:10 pm
content: That minimum for the price is interesting: $27.96 for 1000, or $6.10 for 10000?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 13, 2014, 10:14:52 pm
content: Some stats missing....Total number of resistors in stock.Total resistance of all resistors in stock.

author: rob77
author_rank: Super Contributor
timestamp: August 13, 2014, 10:59:07 pm
content: Quote from: mikeselectricstuff on August 13, 2014, 10:14:52 pmthose are the useless numbers very often required by the management - especially the "total resistance of all resistors in stock" and probably compared to the "total resistance of all resistors in the know universe" to calculate the market share

author: ondreji
author_rank: Contributor
timestamp: August 14, 2014, 12:21:11 am
content: Quote from: mikeselectricstuff on August 13, 2014, 10:14:52 pmTotal number of resistors in stock is 3 127 734 769! (and the other number is almost 1E(xa) Ohm)

author: Smokey
author_rank: Super Contributor
timestamp: August 14, 2014, 01:46:38 am
content: I love it. Don't ever get between a nerd and his data!I've spent all day writing scripts to collect and analyze data like this before with the only end result being me sitting back and thinking to myself... that's cool. now what's next

author: digsys
author_rank: Unknown
timestamp: August 14, 2014, 02:06:27 am
content: +1 :-)

author: chicken
author_rank: Frequent Contributor
timestamp: August 14, 2014, 02:10:26 am
content: I think the price ranges are screwed up. A quick test found 0603 100R for 0.004 @100 and 0.002 @1000

author: free_electron
author_rank: Super Contributor
timestamp: August 14, 2014, 02:53:16 am
content: other statistics missing :power ratingflashover voltagethin or thick filmstatistics like this are nonsense. pick the part needed for the job.i swear by whoever gives me whole reels for free. They throw em at me just so they can be on the BOM.

author: zapta
author_rank: Super Contributor
timestamp: August 14, 2014, 02:55:35 am
content: Quote from: ondreji on August 14, 2014, 12:21:11 amWhat is the average cost of 1 ohm of resistance in stock?

author: ondreji
author_rank: Contributor
timestamp: August 14, 2014, 03:04:08 am
content: Quote from: chicken on August 14, 2014, 02:10:26 amYes, you can say that, I agree. Those prices are based on "Minimum Quantity" column. I didn't scraped individual resistor pages and the price breaks.

author: ondreji
author_rank: Contributor
timestamp: August 14, 2014, 03:12:52 am
content: Quote from: zapta on August 14, 2014, 02:55:35 amSo if you want to buy just one: $1.474 (AUD)Code:Min. 1st Qu. Median Mean 3rd Qu. Max.0.020 0.120 0.430 1.474 0.925 19.930

author: wagon
author_rank: Frequent Contributor
timestamp: August 14, 2014, 03:20:11 am
content: Quote from: amyk on August 13, 2014, 08:48:10 pmI used that system to my advantage recently. Some electrolytics I needed were 6.6 cents each upto 100 pieces and 6.4 cents each for 100-500pieces. I bought 101 pieces. $6.60 for 100 and $6.46 for 101.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 14, 2014, 05:33:28 am
content: Generating a BOM from Altium, you can output the purchase quantity, which includes extra quantity to reach the next price break if it's cheaper. Or you can write a rather tedious Excel expression to do this from the Supplier Pricing field. Which also works (with some changes) if you're building the BOM by hand, copy-pasting the raw supplier data.Occasionally, suppliers themselves will ask if you want to bump an item to the next price break, because it's easier (cheaper) for them, too.Tim