2513	2008-12-19 23:37:42	rcbuckiii	Measuring extremely small value inductors
Message	Date	From	Subject
I'm wondering if anyone has any suggestions on how to accurately measure extremely small value inductors. I have breadboarded several projects lately that use smd inductors. Due to poor tracking of parts as they were removed from the boards I have wound up with unknown value inductors. They are in the 22nF, 39nf, 47nF, and 68nF range. And they don't have any markings to help identify them. I thought of building an oscillator with known values of C and L and then placing the inductor in parallel with the existing one. However, I don't think it would be possible to build an oscillator that would be stable enough to permit accurate measurement of the unknown part. They are cheap enough (50 cent range) I could just toss them and not worry about it and keep track of the parts in future projects. Ray AB7HE
2514	2008-12-20 00:29:36	Dave - WB6DHW	Re: Measuring extremely small value inductors
rcbuckiii wrote: > I'm wondering if anyone has any suggestions on how to accurately > measure extremely small value inductors. > > I have breadboarded several projects lately that use smd inductors. Due > to poor tracking of parts as they were removed from the boards I have > wound up with unknown value inductors. They are in the 22nF, 39nf, > 47nF, and 68nF range. And they don't have any markings to help identify > them. > > I thought of building an oscillator with known values of C and L and > then placing the inductor in parallel with the existing one. However, I > don't think it would be possible to build an oscillator that would be > stable enough to permit accurate measurement of the unknown part. > > They are cheap enough (50 cent range) I could just toss them and not > worry about it and keep track of the parts in future projects. > > Ray > AB7HE > > > Get the AADE LC Meter. It will go down to 1nF with a digital readout. The kit is under $100. Go to > <http://www.aade.com/lcmeter.htm> > Dave - WB6DHW <http://wb6dhw.com>
2515	2008-12-20 07:59:47	Dan Rae	Re: Measuring extremely small value inductors
rcbuckiii wrote: > I'm wondering if anyone has any suggestions on how to accurately > measure extremely small value inductors. > > I have breadboarded several projects lately that use smd inductors. Due > to poor tracking of parts as they were removed from the boards I have > wound up with unknown value inductors. They are in the 22nF, 39nf, > 47nF, and 68nF range. And they don't have any markings to help identify > them. > Get an AADE LC meter. But it measures microHenries for L and microFarads for Cs :^) I'd be lost without mine. Dan ac6ao
2516	2008-12-20 08:24:18	KB9BVN	Re: Measuring extremely small value inductors
I love my AADE LC meter. It's an invaluable tool to take to the hamfest. You can whip it out and measure all those unidentified variable caps, and unmarked coils. Makes it a lot nicer when you KNOW what you are buying. 73 > Get an AADE LC meter. But it measures microHenries for L and > microFarads for Cs :^) I'd be lost without mine.
2517	2008-12-20 08:46:11	Stewart Bryant	Re: Measuring extremely small value inductors
> Get an AADE LC meter. But it measures microHenries for L and > microFarads for Cs :^) I'd be lost without mine. > Dan > ac6ao +1 Stewart/G3YSX
2518	2008-12-20 08:50:55	Jim Larsen - AL7F...	Re: Measuring extremely small value inductors
I also have the AADE LC meter but my latest is the M Cubed Electronix LCRZ meter. From http://www.m3electronix.com/lcr.html Home = http://www.m3electronix.com/ The M3 DIGITAL LCRZ Meter is a multi-frequency impedance measuring instrument capable of measuring resistance, capacitance, inductance, or transformer parameters from 1 milliOhm to 100 MegOhms. The M3 DIGITAL LCR meter has a basic accuracy of 0.2%, has 10 user selectable test frequencies and 6 impedance ranges. This unit is a kit and I found the M Cubed Electonix support to be first rate. My unit worked the first time I applied power. While it does cost more than the AADE it also does more. It is at least worthy of a look. Reviews are found at http://www.eham.net/reviews/detail/6396 http://www.io.com/~n5fc/M3LCR_meter.htm N5ESE Monty review Both the AADE and the M Cubed are great meters. 73, Jim Jim Larsen http://www.AL7FS.us/ Anchorage Alaska (907)345-3190
2519	2008-12-20 08:55:05	Dino Papas	Re: Measuring extremely small value inductors
Ditto on Jim's comments about the M3 LCR meter....love mine as well (along with their semiconductor analyzer). Dino KL0S (Hi Jim -- you might remember me as WB6FZN/KL7 many, many moons ago!). On 20Dec2008, at 11:50 AM, Jim Larsen - AL7FS wrote: > I also have the AADE LC meter but my latest is the M Cubed > Electronix LCRZ > meter. > > From http://www.m3electronix.com/lcr.html > Home = http://www.m3electronix.com/ > > The M3 DIGITAL LCRZ Meter is a multi-frequency impedance measuring > instrument capable of measuring resistance, capacitance, > inductance, or > transformer parameters from 1 milliOhm to 100 MegOhms. The M3 > DIGITAL LCR > meter has a basic accuracy of 0.2%, has 10 user selectable test > frequencies > and 6 impedance ranges. > > This unit is a kit and I found the M Cubed Electonix support to be > first > rate. My unit worked the first time I applied power. While it does > cost more > than the AADE it also does more. It is at least worthy of a look. > > Reviews are found at > http://www.eham.net/reviews/detail/6396 > http://www.io.com/~n5fc/M3LCR_meter.htm N5ESE Monty review > > Both the AADE and the M Cubed are great meters. > > 73, Jim > Jim Larsen > http://www.AL7FS.us/ > Anchorage Alaska (907)345-3190 > > > [Non-text portions of this message have been removed]
2520	2008-12-20 11:16:09	Sam Morgan	Re: Measuring extremely small value inductors
Dave - WB6DHW wrote: > > > rcbuckiii wrote: > > I'm wondering if anyone has any suggestions on how to accurately > > measure extremely small value inductors. > > They are in the 22nF, 39nf, > > 47nF, and 68nF range. And they don't have any markings to help identify > > them. > > > > Get the AADE LC Meter. It will go down to 1nF with a digital readout. > The kit is under $100. Go to > I like the M3 Digital LCR Meter it measures down to 10 nF (0.01uF) http://www.m3electronix.com/featureslcr.html it even has the option of buying it with the SMD Tweezers M3 Digital LCRZ Meter Kit w/SMD Tweezers: $227.00 usual disclaimer, not involved other than just a very happy owner -- GB & 73 KA5OAI Sam Morgan http://linuxbasics.org Linux, the lifetime learning experience.
2521	2008-12-20 12:46:07	Jim Miller	Re: Measuring extremely small value inductors
what's the function of the kelvin clip for the m3? tnx jim ab3cv
2522	2008-12-20 12:52:30	Sam Morgan	Re: Measuring extremely small value inductors
Jim Miller wrote: > > > what's the function of the kelvin clip for the m3? > makes it easier to make measurements, as opposed to the 4 clip lead method. 4 clip lead method can be seen here: http://www.io.com/~n5fc/M3LCR_meter.htm 5th pic down the page, also almost to the bottom of the page is more info -- GB & 73 KA5OAI Sam Morgan http://linuxbasics.org Linux, the lifetime learning experience.
2523	2008-12-20 14:03:58	Michael Clarke	Re: Measuring extremely small value inductors
Dan Rae <danrae@verizon.net> wrote:> rcbuckiii wrote: >> I'm wondering if anyone has any suggestions on how to accurately >> measure extremely small value inductors.>>-- Hi Dan The current issue of Practical Wireless has a neat LCR bridge project with a kit (about £26). May be worth a look. 73 Mick Mi5mtc
2524	2008-12-20 14:03:58	Ashhar Farhan	Re: Measuring extremely small value inductors
an easy way to measure inductance is to plug it into a vfo with known capacitances. this is often not feasible for very small inductances. in such cases all you have to do is mwasure the output frequency after putting the unkown small inductor in series with the known inductor. be careful to keep both inductors isolated from each other. - farhan On 12/20/08, Dino Papas <kl0s@cox.net> wrote: > Ditto on Jim's comments about the M3 LCR meter....love mine as well > (along with their semiconductor analyzer). > > Dino KL0S > > (Hi Jim -- you might remember me as WB6FZN/KL7 many, many moons ago!). > > On 20Dec2008, at 11:50 AM, Jim Larsen - AL7FS wrote: > >> I also have the AADE LC meter but my latest is the M Cubed >> Electronix LCRZ >> meter. >> >> From http://www.m3electronix.com/lcr.html >> Home = http://www.m3electronix.com/ >> >> The M3 DIGITAL LCRZ Meter is a multi-frequency impedance measuring >> instrument capable of measuring resistance, capacitance, >> inductance, or >> transformer parameters from 1 milliOhm to 100 MegOhms. The M3 >> DIGITAL LCR >> meter has a basic accuracy of 0.2%, has 10 user selectable test >> frequencies >> and 6 impedance ranges. >> >> This unit is a kit and I found the M Cubed Electonix support to be >> first >> rate. My unit worked the first time I applied power. While it does >> cost more >> than the AADE it also does more. It is at least worthy of a look. >> >> Reviews are found at >> http://www.eham.net/reviews/detail/6396 >> http://www.io.com/~n5fc/M3LCR_meter.htm N5ESE Monty review >> >> Both the AADE and the M Cubed are great meters. >> >> 73, Jim >> Jim Larsen >> http://www.AL7FS.us/ >> Anchorage Alaska (907)345-3190 >> >> >> > > > > [Non-text portions of this message have been removed] > >
2525	2008-12-20 14:03:59	rcbuckiii	Re: Measuring extremely small value inductors
I was looking at the M3 Digital LCRZ unit and the AADE unit. I was impressed by the M3 and wondering if it was worth the extra money. Based you Jim and Dino's comments I think I will spend the extra bucks for the extra features. You can never have test equipment with too many features. :-) Ray AB7HE
2526	2008-12-20 23:57:13	rmrrisn@flash.net	Re: Measuring extremely small value inductors
While the M3electronix LCRZ meter looks great at first glance, it really isn't suitable (IMHO) for making measurements on components to be used at R.F. frequencies, as the LCRZ meter's highest test frequency is only 15.625 KHZ. Components used at R.F. may well look considerably different when measured at audio frequencies. Specifically, ferrite or iron powder toroids do not have constant permeability/Q characteristics versus frequency. I've encountered capacitors that measured OK when checked on a low frequency LCR meter, yet they had a very high ESR value when measured at 1 MHz. A U.S. manufacturer of capacitors had to correct their manufacturing process when I pointed out this fault to them. They were forced to purchase an HP LCR meter ($10,000) such as I used in order to detect the problem. The N5ESE review mentions this limitation. His L-meter ( http://www.io.com/~n5fc/l-meter.htm ) is a very good approach, but I prefer a variable frequency source as it is useful for determining the self-resonant frequency and any non-linear frequency affects. This website ( http://www.g3ynh.info/zdocs/magnetics/appendix/Toroid_selfC.html ) is quite informative and illustrates the technique that I've used on many occasions. I have an AADE meter and I've found it to be more than adequate for measuring small capacitor values with very good accuracy. L measurements should be questioned as it suffers from the same low frequency limiitation (60 KHz - 750 KHz) if I remember correctly. I would certainly consider purchasing the M3electronix LCRZ meter for making measurements
2527	2008-12-21 20:07:42	Alan Yates	Re: Measuring extremely small value inductors
Ray, The commercial/kit units with direct-reading LCD displays are very nice usability wise, but while you wait for them to ship you can throw together the Carver-style LC testing circuit from page 7.12, figure 7.24 of EMRFD. As long as you have a frequency counter with reasonable resolution and you build a stable fixture for holding the SMDs it should easily be able to measure them accurately enough to tell them apart. I recently built the unit and I love it: http://www.vk2zay.net/article/190 Of course it isn't direct reading, but the maths are simple, and being utterly lazy I wrote a calculator page to do them for me: http://www.vk2zay.net/calc/CarverLCTester One day I'll build a MCU-based display for it just like the kits. -- Alan Yates http://www.vk2zay.net/ On Sat, 20 Dec 2008, rcbuckiii wrote: > To: emrfd@yahoogroups.com > From: rcbuckiii <rcbuckiii@yahoo.com> > Date: Sat, 20 Dec 2008 02:30:37 -0000 > Subject: [emrfd] Measuring extremely small value inductors > > I'm wondering if anyone has any suggestions on how to accurately > measure extremely small value inductors. > > I have breadboarded several projects lately that use smd inductors. Due > to poor tracking of parts as they were removed from the boards I have > wound up with unknown value inductors. They are in the 22nF, 39nf, > 47nF, and 68nF range. And they don't have any markings to help identify > them. > > I thought of building an oscillator with known values of C and L and > then placing the inductor in parallel with the existing one. However, I > don't think it would be possible to build an oscillator that would be > stable enough to permit accurate measurement of the unknown part. > > They are cheap enough (50 cent range) I could just toss them and not > worry about it and keep track of the parts in future projects. > > Ray > AB7HE
2528	2008-12-22 02:35:13	joop_l	Re: Measuring extremely small value inductors
How about making a crystal oscillator with inserting the small inductor in series with the crystal? It is well possible to measure the frequency shift in Hz and relate that to the inductance. In first order the shift will we linear with the inductance since the Lm of the crystal is in the order of milli Henries and thus >> the Lx of the object to be measured. It would of course be necessary to determine the Lm of the used crystal, or to have a reference inductor that gives you the Hz/nH. Expect about 0.2 to 2Hz per nH, depending on the crystal. Joop - pe1cqp
2529	2008-12-22 08:04:40	w4zcb77	Re: Measuring extremely small value inductors