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[?] Looking for a simple way to measure small SM inductors

D

David Chapman

Jan 1, 1970
0
Greetings from London. England.

I've accumulated quite a large collection of small surface-mount
inductors, many of which have lost whatever markings they might have had
in the past.

I know there are some very expensive network analysers and other
devices available that are capable of measuring low-value SM inductors
but I need a MUCH simpler/cheaper way of doing this, specifically with
inductors in the 10nH to 1uH range which are well beyond the scope of
most small inductance meters. I don't need accuracy better than about
20% - just an easy means of ranking values from low to high.

The indirect method that I've used for many years when I have needed
to measure the value of a (physically larger) wire-ended low-value
inductor involves soldering a known-value capacitor across it and then
using a GDO (Grid Dip Oscillator - yes they do still exist!) to find the
resonant frequency, from which I can then determine the inductance.

This arrangement is impractical for tiny SM components so I'm now
considering building up a small range of simple test oscillator units,
each with a small clip to hold the inductor under test. The Maxim
MAX2605-2609 range of low-cost VCO ICs look ideally suited for this job
since they can oscillate over frequencies from 45MHz to 650MHz with
inductor values between 1.8uH and 4nH.
I could then measure the oscillator's output with a frequency counter
and determine the inductor value using a look-up table, or alternatively
I could just measure the actual tuning voltage required by the VCO to
produce a specific output frequency for a particular value of inductor.
Obviously it would be necessary to determine and make allowance for
the stray inductance/capacitance introduced by the clip arrangement by
testing each oscillator using accurate known values of inductance.

Has anyone in this NG any comments or constructive suggestions to make
about this idea? Alternatively, can anyone suggest any suitable low-cost
(< $200 or so) devices that can measure small SM inductors?

TIA - Dave.
 
L

legg

Jan 1, 1970
0
Greetings from London. England.

I've accumulated quite a large collection of small surface-mount
inductors, many of which have lost whatever markings they might have had
in the past.

I know there are some very expensive network analysers and other
devices available that are capable of measuring low-value SM inductors
but I need a MUCH simpler/cheaper way of doing this, specifically with
inductors in the 10nH to 1uH range which are well beyond the scope of
most small inductance meters. I don't need accuracy better than about
20% - just an easy means of ranking values from low to high.

The indirect method that I've used for many years when I have needed
to measure the value of a (physically larger) wire-ended low-value
inductor involves soldering a known-value capacitor across it and then
using a GDO (Grid Dip Oscillator - yes they do still exist!) to find the
resonant frequency, from which I can then determine the inductance.

This arrangement is impractical for tiny SM components so I'm now
considering building up a small range of simple test oscillator units,
each with a small clip to hold the inductor under test. The Maxim
MAX2605-2609 range of low-cost VCO ICs look ideally suited for this job
since they can oscillate over frequencies from 45MHz to 650MHz with
inductor values between 1.8uH and 4nH.
I could then measure the oscillator's output with a frequency counter
and determine the inductor value using a look-up table, or alternatively
I could just measure the actual tuning voltage required by the VCO to
produce a specific output frequency for a particular value of inductor.
Obviously it would be necessary to determine and make allowance for
the stray inductance/capacitance introduced by the clip arrangement by
testing each oscillator using accurate known values of inductance.

Has anyone in this NG any comments or constructive suggestions to make
about this idea? Alternatively, can anyone suggest any suitable low-cost
(< $200 or so) devices that can measure small SM inductors?

TIA - Dave.

http://www.aade.com/lcmeter.htm

RL
 
D

David Chapman

Jan 1, 1970
0
I
Many thanks to all of those ho took the time to reply to my posting.
I'll be ordering one of the L/C meters very soon - it looks ideal for
the job..

73 - Dave.
 
M

m II

Jan 1, 1970
0
"m II" wrote in message
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My 'GymyBobism' collection...updated daily:
=========================================
## some '#' bracketed text added for clarification ##
## all cut and paste, NO modifications of ANY kind ##
## 100 % Pure GymyBob. Accept no substitutes! ##



We need less morons like another clone of Moron II here.
## My fifteen minutes of FAME! ##


Your car alternator will charge your car batery up to 15.4 volts in
cold weather.

NTSC redefined it slightly off 60Hz so that power supply ripple
will move on the screen (two slightly black bands that scroll
up/down your screen

You sure spent a lot of time trying to convince me you don't knwo what
I am talking about...LOL

Voltage does not indicate state of charge well.

At 11.6 volts a 12v battery is about 50-70% charged still.

Polish solar panels are what americans called "flashlights"

There should be subsidies for solar panels but control of prices to boot.

Propane will disapate and freeze when it evaporates.

Gasoline is not nearly as volatile as hydrogen.

When I use pot I imagine everythging is perfect.

Many people have browsers that economize the download

Just another threading error creating confusion

Learn how to thread or sit back and watch for a few years.

Try to stay on topic and on thread too bean brain.

Perhaps try Outlook Express or another browser that knows how to
thread posts.

Bottom posting was the was in the 70s and 80s before threading
browsers were available cheap like OE

Another Forte Agent person that doesn't understand threading.

You use Mozzilla and haven't learned to thread.

Try Outlook Express so you can understand threading maybe.

I have been noticing many threading errors everywhere on Usenet lately.

People with OE don't seem to have the petty problems with subject
lines changing, intermingled posts and downloading binary files with
mixed posts, random pieces and many other problems all the nonOE
people have.

Bottom posting has been obsoletely by threading browsers.

Forwarding does not include headers.

Call your damn ISP and tell them your browser is multiple posting.

90% of the people in America have never operated a computer.

Let's say youre solar cell was trying to put out
14.3 volts DC and you stuck a 10 ohm meter in series with a charged
13.8 volt DC battery.

Your troll was too obvious. Try to engage the mark in conversation
first so there is, at least, some stake, like friendship for the
person listening. When the friendship is well developed then attack.
Not too obvious at first or you will lose your audience. This will
enhance your troll points.

I think outside opinions are worth much more than sales hype from the
company that made the product.
## Referring to *factory* charging specifications for the batteries
they make ##

This is power grid induction through capacitive proximity

You can get fooled with another ground in the house finding it's way
back to the transformer neutral.

A thought I have is rain water from a roof on a three story home
through a micro-turbine.

Setback thermostats only work efficiently for small differentials,
dependant on the time duration.

Breakers are good for one time usage of one fault and then they need
to be replaced for any warrantied usage.

If the breaker interupts a fault, it should be replaced.No warranty
will honoured after that.

I don't have a link at this time

There are no hydrogen molecules in water and the oxygen in water isn't
flammable either.

Water is inert and contains no energy to be used. Get some basic chemistry
first.

Quite simply put, for some of the boneheads here.

NiCads and NiMh batterries are designed to take a current charge forever.

Oh yeah, I can charge a battery and use it six months later fully
charged. The nicads will be cooked because you keep them on charge,
just in case you need them but when you remember them six months
later they are cooked and won't last 5 minutes in the camera.

It takes a complete idiot to deny they can short out all by
themselves. Three, loose in a bag can short themselves out.
## referring to AA batteries doing the physically impossible ##

Did they have electricity back in 1994?

I have been around so long with this stuff I believe I invented the
diode in 1941 but I am not familiar with the solar panel usage
requirements of them. (no P & N substrate explanations please. I wrote
the GE manual...LOL)

NOTE: do not pass ground wires through metal holes or cable clamps
with two screws on a metal surface.

There is **NOT*** enough energy in a lightning bolt to power your
house for more than an hour...if that. Do the math.
The figures escape me but let's say it puts out a roughly MWatt of
power for 100 nanoseconds?
100 x 10-9 x 1 x 106 / 3600 (sec/hr) = 0.0027 wH
oooops.... Wouldn't light your home for a 1/2 second.
OK..OK.. multiply the figures time 100 or 1000. Now it would light a
100W bulb for 1 second.

The IEEE-232 standards were never followed or known by many.

Fossil fuels are still renewable and being cxreated as we speak.

Children are venerially created.

If you want to discuss this then fine, otherwise go **** yourself like
your mother did.

Can you let go of my dick before it explodes on ya, goofball?

Petroleum is not related to Natural gas.

I would rather work at my $100/hour job than at chopping wood for
hours to save $3/hour

I have no license, I wire and inspect other's wiring for a job and
work for a medium size electrical utility.

As a design engineer of transformers for 10 years I happen to know you
are full of shit.

I am a Protection & Control Tech by profession and have experience
with control systems

Try spelling "bus" correctly! Maybe your brain will start again.
Probaby not, you fucking loser.
## Referring to the correctly spelled word 'buss' as used in real
electrical terminology ##
## http://tinyurl.com/5ctml ##

X10 signals are transmitted just after the voltage waveform zero
crossing. This is in order to avoid conflicts with SCR and Triac peak
waveform switching spikes from load type devices such as lamp dimmers.
## control module misinformation ##

Besides when they on any line they will pull of the meter as a
disconnect point.
## speaking of power line guys miles away removing YOUR electrical
meter for THEIR safety ##

My workplace has been throwing out huge digitizing pallettes (like 24
x 36" units)
## in alt.sewing.mach-embroider ##

The majority prefers top posting.

Not one of your suggesters listened to what the OP requested...LOL

Get your tear ducts flushed by a knowledgeable optometrist.

Not many materials have the huge exponential resistance/heat curve
aluminum does. Overload doesn't make it glow like copper...it flashes
and explodes.

A bathroom fan motor would never push hot air down ten feet or cold up
ten feet.

Bathroom fans have a hard time pushing 55 cfm through a 3-4" pipe 20
horizontal feet. They are made to vent smells and humid air horizontally
only.

Why not spend the money on a contract with the grid company and get an
exclusive line to your house and never have brownouts.

Usenet rules dictate top posting for readability

Many cell modems are set up to filter bottom posts out.

Cell modems do not cut off anything.

What security flaws.
##referring to Outlook Express##

10 pounds per gallon Imperial. That gallon is totally unique to the
US....ooops..I think all gallons are unique to the US now.

The standard Imperial gallon the whole world used weighs 10 pounds
exactly.

The copper isn't worth more than 5 cents per pound. It is classed a
mixed copper and nobody wants it.

Hey moron! The copper is considered "mixed" copper and is worth about
$0.02 per pound, if he seperates it all.

Just don't ever lose weight. Toxins are stored in your fat cells.

Did you know, **NO***, I repeat ***NO*** death has ever been related
to PCBs?

Insulated square copper wires from a dry transformer are not 99%
copper and take a lot of work to remove the insulation.

I have tonnes of insulated copper wire if you want it. I think you
could almost have for the picking it up. How many bins can you take
per year

50 lbs? We have it by the bin full. Mostly #6 to 650 MCM. I beleive
you would have to leave a bin and then pick it up full later to
compete with the current scrapper.

Can't this tranformer be used by somebody to generate a second 120V
from a single phase 120V inverter? It sounds pretty beefy.

BTW: once you knock the wedge out of the coil form the laminations
will be easier to get out. This keeps them from buzzing until the
varnish and other impregnations go into it.

All you guys have a bad Christmas or Jewish and didn't see Santa or
something?

Run each signal twisted with a ground for noise. RD twisted with gnd
as a pair, TD twisted around ground as a pair etc... This means
signal/logic ground not power ground or case ground, if they are
different. Do not
connect the other ends of the ground conductors.

Tar pitch in a flourescent ballast does ***NOT*** contain PCBs and
probably never did.

Religion is not genetic or even herodigious

I believe the warmest part of the lake is just below the ice. As the
water frezes it rises to the top and joins the other ice formations.

Gel cell won't cut it when it comes to putting out 100A or more. They
cook in one spot and the rest of the electrolyte doesn't circulate
fast enough.

There is nothing standard about USanian measurements. They changed
their sizes to avoid trading with the rest of the world. This worked
for a few centuries but the rest of the world moved on to the metric
system to avert the confusion the US caused.

Ever put your ohmmeter (do I need to explain an ohmmeter also?) across
a capacitor? It measures infinity after charging to the supply voltage
because the electrolyte is an insulator.

Electrolytes are not conductors of electricity in a capacitor.

If the electrolyte conducted it would be a resistor.

I doubt they are 4 farads. More likely 4 microfarads uf.
## referring to 4000mfd caps ##

Sometimes it is an ego boost to have these so-called "professionals"
come and beg for information because they can't our toys do what the
good guys can but I would never hire them given a choice.

Do you measure altitude in degrees? Many aeronautical people would
disagree with you.
## referring to solar azimuth/altitude thread ##

My house is filled with motion detectors. They don't all operate
lights. They mostly signal my house control computer and it decides
what to do and when.

Enlighten please (like it really matters...LOL)

I will hand stitch my embroidery before I would pay that kind of
money...LOL

A 50Hz transformer needs double the iron a 60Hz transformer needs for
the same VA capacity.

Does it test CTs with real current or just voltage?

It doesn't really matter where the secondary current comes from,
secondary exciting or primary current exciting, the voltage developed
or excited across it will be about the same.
## talking about an OPEN circuit CT transformer ##

High voltage spikes want to keep going at the end and this is where
your saturating core transformer core is located behind the fuse.

Moving a kill-a-watt unit around is like using it on somebody else's
house and telling the person's load.

oooops. A flourescent with a filament?
## not knowing how most fluorescents start up ##

You are a stupid basterd.

Ever considered anxiety medication? Chest pains for a man is a classic
symptom.

When confronted with many websites stating the otherwise he won't
address the issue but repeats his crap again like a child stamping his
feet.
## Oh, the Irony! ##

What are you doing up at this ungawdly hour? I just got finished
embroidering about 10 items, including a flight bag for golf clubs.
## in alt.sewing.mach-embroider ##

I just love women with front loading bobbins.
## in alt.sewing.mach-embroider ##

I doubt a 6 needle machine would be faster than a 1 needle machine
unless you do repetitive patterns.
## in alt.sewing.mach-embroider ##

I had many problems with this and damaged my machine a few times. It
was the needles. Find ones that have very little "hip" bump around the
eye of the needle.
## in alt.sewing.mach-embroider ##

I have found doctors absolutely ignorant and totally obstinet on
these kind of issues.

I put my first child on Ritalin for a year or so when quite young. It
beat going to prison for beating him black and blue.

I made a big mistake and should have "drugged" all of my children the
same.

I did the chem.cut medication stuff for a few years with my first
child and then found Naturopathic Doctors using homeopathy to get more
lasting relief.

Homeopathics saved me thousands of dollars for operations I did not
have on my children

Accupunture worked for my 1 and two year old children for ailments
after the medical doctors could do nothing for.

Placebo is a completely natural cure for many ailments.

Polio Vaccine? They stopped giving that one long before HIV was invented.

You have no idea what you are talking about and either does anybody
else here.

See if you can replace it with a thermal acting unit. They have a
rachet on a shaft that holds thew contacts closed.
## confusing motor overload with breaker ##

What are you doing in my group?

Milk is just plain poison for humans.

I am not a chemist but I know that cow's milk calcium molecules are a
huge irritant to human digestion and usually results in calcium
deficiencies

See an accupunturist for the pain and circulation
See a chiropractor to keep the structure good.
See a naturopathic doctor for the chemical imbalance.
See a medical doctor for a some poison that will make her life shorter.

Even an honest Doctor will take yoy they arte totally ignorant of
nutrition.

The medical doctors will play the time game and probably just let him
die after removing half his organs because they may be a problem.

Some things mankind should just not eat too much of and it isn't meat
typically and this may not be consistent for all people.

Do not listen to the stories of addiction. Yes, they are tough to stop
but so is insulin for a diabetic. I have stopped taking mine and it
wasn't that bad but after months of regressing I chose to return like
the other half the population.

Make sure your wrists are well warmed up before putting sudden jerky
movements to them.

Make up your mind before you mouth off like the usual Internet piece
of shit. This is a rough group and if you had followed the usual
recommendations you would have known that and have nothing to say
about it.
## in misc.kids.health, alt.support.breast-implant,
misc.health.alternative ##

Bad practice to ground yourself when working on electronics. It
increases the chance of injury or death by electrical shock and also
increases the chance of static discharge to the circuit chips. Ground
is a potential too.

Oink...Oink...just take it out. What could be simpler?
## in soc.support.fat-acceptance, alt.support.big-folks ##

No hyphen in the word multi-syllabic.

## Gymy Bob's endorsement of anal sex censored##
## sorry, I have my limits ##

A complete fucking idiot spurted out his piehole:
## in misc.health.alternative ##

I was born depressed and never realized until about 3 years ago. I am
52 and went for medication because of anxiety.

The English can't stand each other, let alone other cultures.
If you don't believe me brother just ask the rest of my family that I
disowned.

I find most Americans likeable and they find me likeable after they
open their wallets far enough to make me that way.
How many american dollars will it take to make you suck their dicks?
## in alt.support.attn-deficit, misc.health.alternative ##

How much for a blow job?

Believe me, "America" is so far behind on internet usage over many
South American countries. They just don't happen to post in English
and not many of you could possibly understand other languages even exist.

WTF is CBT? Chekaslovakia Book Therapy?

Try your left hand. It feels like somebody else's hand sometimes.
## pdaxs.services.massage, misc.health.alternative, alt.backrubs,
alt.health.massage-therapy ##

OK, you're not a moron. You are above average for Nova Scotia.

Another tidbit for the brainless twit with the big mouth here

Pehaps magnesium supplementation would allow these buffoons to utilize
some
of their already overloaded calcium intake.

This guy is a total buffoon and has no knowledge of any part of his
own sentence.

Where should you shove it?

Fish oil is mainly responsible for your placebo also.
## in misc.health.alternative##

After disassembling Bill Gates' 6800 Basic back in the 70s I knew he
was a dirty software scoundrel.

The government makes more on the taxes than the tax rate when this is
done.

Be blabest tofart.
## ???? in alt.comp.periphs.dcameras ##

Blood may be kept at a stable 7.4 pH but a piece of copper wire passes
electricity through it even though the number of electrons remains
constant.
## in misc.health.alternative ##

I have had amazing effects from some homeopathic remedies and others
did nothing.

These homeopathic know-it-alls drive me crazy with their 1880 knowledge.

Sorry, but testing has proven homeopathic remedies to be effective
remedies.

I have taken a few homeopathic remedies that taste like crap. Funny
how pure
water could do that.

Homeopathic remedies are very toxic substances and used because of
their toxic properties.

Standard homeopathic science.

Your ignorance of homeopathy does not mean it is useless.

Everybody always follows the screaming, left-wing, maniac, tooting we
are all going to die by doing another therapy.

I have had achilles tendonitus for the past 2-3 years now. I got rid
of it on one side by grinding out the bones spurs underneath with the
side of a screwdriver blade and lots of oil.

GET OFF THE WHEAT, CORN & OATS!!!

It doesn't matter how well it works if the doctor doesn't say so (with
his two years of college) then it just ain't so.

Heat pumps are 300% efficient when the weather is fine but the
compressor motors? hmmm about 60%.

You are obviously a moron and you keep repeating it here.
## referring to my corrections of his postings ##




the genuine mike



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C

Clifford Heath

Jan 1, 1970
0
Mike,

You can buy a very nice kit for basically the same circuit:

<http://www.altronics.com.au/index.asp?area=item&id=K2533>

I built one and have had hours of fun with it. The MCU is
pre-programmed, so the only real challenge in assembling
it is working around a small mechanical alignment problem.
Accurate and well worth the price.

Clifford Heath.
 
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