Is this the so called zero ohm resistor? - Page 1
Forum section: electronics / projects

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 25, 2019, 05:01:18 pm
content: Is this a zero ohm resistor? My dmm shows 19kohm

author: oPossum
author_rank: Super Contributor
timestamp: September 25, 2019, 05:02:18 pm
content: That is a thermistor.

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 25, 2019, 05:09:25 pm
content: Are you sure ? Check this link at wiki they seem identicalhttps://en.wikipedia.org/wiki/Zero-ohm_link

author: mikerj
author_rank: Super Contributor
timestamp: September 25, 2019, 05:18:17 pm
content: Quote from: sdancer75 on September 25, 2019, 05:09:25 pmThe component on your board has a glass package, the zero ohm link in the wikipedia picture is a ceramic part. I agree with oPossum, it looks very much like an axial thermistor.

author: ogden
author_rank: Super Contributor
timestamp: September 25, 2019, 05:18:40 pm
content: Quote from: sdancer75 on September 25, 2019, 05:09:25 pmFar from identical. Following looks much more "identical":https://www.littelfuse.com/products/temperature-sensors/leaded-thermistors/glass-encapsulated-thermistors.aspx

author: Kilrah
author_rank: Unknown
timestamp: September 25, 2019, 05:18:54 pm
content: The band on the zero ohm resistor is a marking. There is no printed band on your component, you just see the 2 halves of the innards through the glass.And your DMM measures 19K, which is not 0.

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 25, 2019, 05:33:09 pm
content: Quote from: ogden on September 25, 2019, 05:18:40 pmThat's it ! Thanks

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 25, 2019, 05:35:07 pm
content: Quote from: Kilrah on September 25, 2019, 05:18:54 pmThought of bad resistor.....

author: Kilrah
author_rank: Unknown
timestamp: September 25, 2019, 06:17:08 pm
content: It would be burnt to hell if it had broken.Also I've never seen a resistor in such a glass package.

author: Howardlong
author_rank: Super Contributor
timestamp: September 25, 2019, 06:21:49 pm
content: Then there is the ultimate nerd and pedant paradox, it can’t be a resistor if it’s zero ohms.

author: helius
author_rank: Super Contributor
timestamp: September 25, 2019, 07:18:04 pm
content: Quote from: Howardlong on September 25, 2019, 06:21:49 pmEven a (normal)conductorcan't be zero ohms! Only superconductors can.But in practice we only care about resistances that visibly affect the circuit. In low-power or signal circuits, several milliohms is as close to zero that the difference isn't significant. In high-power delivery systems, those milliohms matter a lot more.

author: Kilrah
author_rank: Unknown
timestamp: September 25, 2019, 07:26:23 pm
content: Quote from: Howardlong on September 25, 2019, 06:21:49 pmWe should probably call it the "insignificant resistor" then... or "packaged wire"

author: Bud
author_rank: Super Contributor
timestamp: September 25, 2019, 08:01:26 pm
content: Put your finger on it while measuring, problem solved.

author: Gyro
author_rank: Super Contributor
timestamp: September 25, 2019, 08:22:28 pm
content: Quote from: Howardlong on September 25, 2019, 06:21:49 pmI have to admit that I find the fairly common practice of suppliers listing them as +/- 5% tolerance is rather amusing. Definitely worth getting a batch and weeding out those -5% ones.

author: ogden
author_rank: Super Contributor
timestamp: September 25, 2019, 09:16:33 pm
content: Quote from: Gyro on September 25, 2019, 08:22:28 pm0R with proper datasheet have non-zero resistancespecified. In result +/-5% spread do not look weird anymore and you can put away your free energy generator plans.

author: RoGeorge
author_rank: Super Contributor
timestamp: September 25, 2019, 09:29:21 pm
content: I don't see a zero ohm resistor, that's a thermistor.19 Kohm at room temperature is a common value. Heat it with the finger or with something else while measuring its value and you should see how the resistance changes.

author: soldar
author_rank: Super Contributor
timestamp: September 26, 2019, 01:40:04 pm
content: Quote from: Gyro on September 25, 2019, 08:22:28 pmThink again. No matter how small the value, even zero, you will never get a negative value by subtracting 5%. Or 50%.