Why are low value resistors so expensive? - Page 1
Forum section: electronics / beginners

author: level6
author_rank: Regular Contributor
timestamp: February 28, 2020, 04:16:39 pm
content: I was shopping for some 500 ohm resistors on Mouser and boy are they expensive! Is that because of low demand or is it due to manufacturing costs?

author: Kleinstein
author_rank: Super Contributor
timestamp: February 28, 2020, 04:19:48 pm
content: 500 ohms is not in the normal E24 / E96 series. One can still get them from the precision series. Chances are 510 Ohms or 470 Ohms can be cheaper and more (lower cost) types to chose from.500 Ohms is not especially low - things can be different at 500 µOhms or nOhms.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 28, 2020, 04:29:12 pm
content: get a 499 ohm and 1 ohm, or simply 499 will do, why you need so accurate? circuit that needs that accurate value, if not exceeding few GHz BW is flawed imho. few minutes ago i concluded on my order in lcsc, some of them are various values of smd resistors. i skipped the 0.01 ohm 0603 type because it was unusually 10X more expensive than the rest, although the bigger 0.01 ohm 0805 is finely priced, go figure. unluckily 500 ohm value also not available in lcsc, out of stock or not currently made not sure. otoh, i was having difficulty getting 50 ohm resistor, so i just get the 49.9 ohm, next candidate is 50.1 ohm, should be not far off...

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 28, 2020, 05:20:16 pm
content: E-12 is probably the cheapest, E-24 and E-96 slightly more expensive.Every factor thats makes a resistor "more unusual" adds to the price.It does not even have to be a "special thing", just the lower prodution numbers makes it more expensive.Then there are the "special requirements". Tolerances below 0.1% become more expensive quickly.Low tempco or low inductance adds to the costs.High dissipation and other factors.If you're wondering about specific resistors, then post more info or direct links.

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2020, 08:27:23 pm
content: Quote from: Mechatrommer on February 28, 2020, 04:29:12 pmTwo 1k resistors in parallel would be the usual method to get exactly 500 ohms using standard values. The precise value might be required for a divider.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 28, 2020, 08:31:27 pm
content: yup but its a sure way to get 2 resistors on a board. probably one 499 will just do the job as well.. ymmv.

author: David Hess
author_rank: Super Contributor
timestamp: February 28, 2020, 08:46:16 pm
content: Quote from: Mechatrommer on February 28, 2020, 08:31:27 pmI once wrote a program to find exact ratios using standard value resistors. But often it is better to use multiple resistors of the same value in series and parallel combinations because the identical resistors are likely to track better. It also minimizes the number of different parts required and may make availability easier.

author: Gyro
author_rank: Super Contributor
timestamp: February 28, 2020, 09:37:07 pm
content: 'Fun With Resistors' is my favourite resistor combination calculator so far...https://www.eevblog.com/forum/projects/fun-with-resistors/Although Rescalc is very simple and perfectly useable for single resistor substitutions too...http://www.pmillett.com/rescalc.htm

author: TimFox
author_rank: Super Contributor
timestamp: February 28, 2020, 09:49:39 pm
content: This discussion requires a definition of the acceptable tolerance for the resistorin the application, as well as the power level. In higher power wirewound resistors, even values such as 500 ohms are more popular than E12 or E24 values such as 470 and 510.

author: jeroen79
author_rank: Frequent Contributor
timestamp: February 29, 2020, 09:35:25 pm
content: Quote from: level6 on February 28, 2020, 04:16:39 pmWhich ones did you find?I can find them as low as 14 cents a piece and as high as 243 euros a piece:https://nl.mouser.com/Passive-Components/Resistors/_/N-5g9n?P=1z0x8b9Z1y95kbvZ1y95kblZ1y95l7nZ1y95kbpZ1y95l83Z1y95kc7Z1y95kc2Z1y95jjmZ1y95jjs&Ns=Pricing%7c0

author: Kirr
author_rank: Regular Contributor
timestamp: March 01, 2020, 01:41:27 am
content: Quote from: Gyro on February 28, 2020, 09:37:07 pmThanks, I added these two tools to the links of my tool.For the calculators, you can also try my network finder:http://kirr.homeunix.org/electronics/resistor-network-finder/