Can't measure certain resisitors with my dmm - Page 1
Forum section: electronics / beginners

author: Gosub
author_rank: Contributor
timestamp: October 26, 2014, 03:19:08 pm
content: Hi people,I am new to electronics and have a question. Why can't I measure this resistor pictured below, I pulled about 30 of them from an old home computer and all give a quick indication then go straight out of limit. I have tried with both the DMM's pictured.If you are wondering why I am measuring them, I was just testing my new DMM'sIs it because the resistors are outside the spec of the DMM's? Am I using the wrong measurement tool for this job?Thanks in advance for any help

author: Neilm
author_rank: Super Contributor
timestamp: October 26, 2014, 03:24:50 pm
content: First thought - have you tried two different sets of test leads? There is only one set in the picture. Short the test leads together to check they are not open circuit

author: Gosub
author_rank: Contributor
timestamp: October 26, 2014, 03:31:10 pm
content: I tried with a different set and also a third cheap dmm gives same result.Are these resistors damaged easily with thermal shock?I de-soldered with a vacuum de-solder station from duratool

author: Simon
author_rank: Unknown
timestamp: October 26, 2014, 03:33:07 pm
content: is that red, red, orange, green ? 22'300'000 22.3M ?

author: Gosub
author_rank: Contributor
timestamp: October 26, 2014, 03:34:55 pm
content: I believe it's Red, Red, Orange, Grey,

author: Fraser
author_rank: Super Contributor
timestamp: October 26, 2014, 03:36:31 pm
content: They are not resistors....they are CAPACITORS !Coloured rings are not limited to just Resistors. They are also used on inductors and capacitors. Your part is the latter. Its the shape and pink colour of the background that gives it awayTest them with a capacitance meterCapacitor Code for you:http://www.electronics-tutorials.ws/capacitor/cap_5.htmlAurora

author: Gosub
author_rank: Contributor
timestamp: October 26, 2014, 03:42:34 pm
content: Thank you kind sir, I didn't realise capacitors came in this package.Is there any way of differentiating between capacitors and resistors from a visual point?Thanks again for the lesson friend, my noobiness is really showing I guessRegards all

author: Gosub
author_rank: Contributor
timestamp: October 26, 2014, 03:43:07 pm
content: They were 19 nF by the way

author: Fraser
author_rank: Super Contributor
timestamp: October 26, 2014, 03:45:39 pm
content: Gosub,No. others in this thread also thought the same as you and we all have to learn so no worries for asking. I met these types of capacitors many years ago and they are no longer common so it is not surprising that you did not recognise themI have added to my last post and provided a link to a colour code chart for you.Aurora

author: SeanB
author_rank: Super Contributor
timestamp: October 26, 2014, 04:37:11 pm
content: Capacitors, and they were common in older computers that used DIP IC's. Inside you will find a ceramic chip capacitor with leads on it, in an epoxy or glass overcoat. In IBM machines you often got them in a clear glass package where you could see the capacitor chip inside, with the value printed in fine red lettering on the body.

author: krish2487
author_rank: Frequent Contributor
timestamp: October 26, 2014, 06:15:33 pm
content: QuoteI am just generalizing here.Generally resistors have a blue body for Metal Film variety.Carbon film resistors are greyish and wirewound resistors are generally , but not limited to, red body. Actually wirewound resistors are dependant on the dye that the manufacturer wishes to use and/or has available.Inductors have a sort of a lightish green body.Capacitors, apparently, have a pink hue.I knew about the resistors and inductors but the capacitors are as much a new bit information for me.

author: tautech
author_rank: Super Contributor
timestamp: October 26, 2014, 06:52:26 pm
content: Quote from: Aurora on October 26, 2014, 03:36:31 pmHats off to youAuroraUnless I had tested them with my Smart tweezers they would have bluffed me too.I have resistors with a "pink hue" too, just tested them.IMO body color can not be used as a guideline to identify them, trust your DMM.Quote from: krish2487 on October 26, 2014, 06:15:33 pmWell I have resistors in all these colors plus some, we mustn't make generalizations.Small list:CreamCream with pink hue3 shades of blue3 shades of greenGreyPurpleBrownRedSMD is much simpler.

author: Simon
author_rank: Unknown
timestamp: October 26, 2014, 06:54:25 pm
content: Quote from: tautech on October 26, 2014, 06:52:26 pmAgreed, if in doubt - bin it

author: krish2487
author_rank: Frequent Contributor
timestamp: October 26, 2014, 07:27:21 pm
content: @tautechCorrect!!!Forgot to add brown for the wirewound type!!!Thanks...The generalizations provide a reference for the passive type to measure i.e whether the passive in question is L/C/R.It is certainly better than no reference at all..Having said that, when in doubt. eliminate by verification!!

author: SeanB
author_rank: Super Contributor
timestamp: October 26, 2014, 07:48:04 pm
content: Get the component tester for $20 talked about in other posts, then you will get a good idea as to what it is easily.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 27, 2014, 04:32:36 am
content: This works the other way,too!I've run across resistors which look like small silver mica capacitors.(A bit like a leaded ceramic cap package,but glossy).My mate was getting funny results & brought a "cap" down to where I had a LCR tester.It again tested as a resistor,so we traced the circuit out,& it was.