Do I really need an LC meter?

N

notbob

Guest
I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is the
toroids. Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing. Any comments?

nb

--
vi --the heart of evil!
 
"notbob" <notbob@nothome.com> schreef in bericht
news:slrnjp4bmo.2nd.notbob@nbleet.hcc.net...
I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is the
toroids. Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing. Any comments?

nb

--
vi --the heart of evil!
Click to expand...
A LC-meter is a usefull piece of equipment - at least for me. I build Phil
Rices LC meter
http://www.marc.org.au/ though a designed my owm PCB. It's very good for
measuring capacitances and I get at least an idea about coils. But measuring
coils is tricky. Except for air core types, inductance depends highly on the
frequency which may not be the frequeny used by the LC meter. So for
measuring inductance accurately it's better to use a griddipper or similar
and measure in the frequency range the coil is intended for to be used.
Measuring toroids require some additional tricks as the magnetic field of it
hardly radiates.

petrus bitbyter
 
On Fri, 21 Apr 2012, notbob wrote:

I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is the
toroids. Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing. Any comments?

It's a neat gadget, but people lived without them in the past. And while
Click to expand...
you can get a DMM for ten dollars and definitely get value out of it
(especially considering that analogue meters in the old days were pretty
awful at that low a price), the ones that measure inductance are in a
different price range. The standalone are obviously better, but will cost
money.

It's important to note that many DMMs above the cheapest price now measure
capacitance, one reason I bought a new DMM about 1996. But they are
biased towards larger values, since the built in capacitance is larger
than some small value capacitors that you'd use in RF.

People always used to wind coils without an inductance meter. They'd wind
it according to a chart, or the math, or just follow what someone had
described in the magazine. Generally, it was okay. But no matter what,
often you'd have to make adjustment anyway, so coils were wound on forms
that had a core that could be adjusted to tune the coil, or a variable
capacitor was in parallel with the coil. With toroids, the variable
capacitor would have to be used. Note that a lot of construction articles
will never tell you the inductance of the coil, they'll just tell you how
to wind them.

You'd need some sort of test equipment, a signal generator or something
makedo to peak the coil for the desired frequency, but often one could
makedo with something rather than buy an expensive LC meter or signal
generator.

Michael
 
"notbob" <notbob@nothome.com> wrote in message
news:slrnjp4bmo.2nd.notbob@nbleet.hcc.net...
I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is the
toroids. Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing. Any comments?
Click to expand...

The Peak Atlas LCR meter isn't too pricey at about 4-5x the price of a
cheapo DMM.
 
Maybe.
You can use a DMM that measures capacitance to also measure inductance.
Google for how to do that.
But you need to realize that just measuring inductance that way is not
necessarily what you need. Why? Because the effective inductance
value, in many cases, depends on the current going through the inductor
and the frequency of use (inductors have capacitance too). So you need
to understand more than simple inductance. Google around for more
tutorials on types of inductors (core material, capacitance) then
decide what you need to measure.

--
So where are we?
Not the street address.
Not the city.
Not the country.
Not the Earth.
Not the Solar System.
Not the Galaxy.
Not the Universe.
Not the Brane.
So where is the Brane?
Where are we?

Life is but a dream!
 
On 21 Apr 2012 03:50:14 GMT, notbob <notbob@nothome.com> wrote:

I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is the
toroids. Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing. Any comments?

nb
You could learn to do it the old fashioned way. Measure the impendence
Click to expand...
at the operating frequency, measure the DC resistance, and use some
light math. It will get you close. But then you would need equipment
to do that. I'll see if I have a spare LC meter in the shed.

Tom
 
On Sat, 21 Apr 2012 13:08:36 +0200, petrus bitbyter wrote:

"notbob" <notbob@nothome.com> schreef in bericht
news:slrnjp4bmo.2nd.notbob@nbleet.hcc.net...
I'm still a rank newb, but have dived right in. Besides the Arduinos
and other silliness, I have a SoftRock RX kit. Requires a couple SMT
devices, but am almost fully geared up fer that. The other thing is
the toroids. Assy vids look straight forward enough, but do I need an
LC meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get in
on the ground floor of cap and choke testing. Any comments?

nb

--
vi --the heart of evil!

A LC-meter is a usefull piece of equipment - at least for me. I build
Phil Rices LC meter
http://www.marc.org.au/ though a designed my owm PCB. It's very good for
measuring capacitances and I get at least an idea about coils. But
measuring coils is tricky. Except for air core types, inductance depends
highly on the frequency which may not be the frequeny used by the LC
meter. So for measuring inductance accurately it's better to use a
griddipper or similar and measure in the frequency range the coil is
intended for to be used. Measuring toroids require some additional
tricks as the magnetic field of it hardly radiates.
Click to expand...
I second the motion for a grid dip meter -- because it's useful for so
many other things, too.

Or a signal generator and a demodulator probe -- you can usually get a
nice sharp dip with a series LC and the right resistance.

Or -- just wind your coils. I've had good luck with winding toroids on
Amidon cores. Unless you're trying to use some toroid made out of
mystery material, you can pretty much build it to print and expect it to
work.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
 
On Apr 20, 11:50 pm, notbob <not...@nothome.com> wrote:
I'm still a rank newb, but have dived right in.  Besides the Arduinos
and other silliness, I have a SoftRock RX kit.  Requires a couple SMT
devices, but am almost fully geared up fer that.  The other thing is the
toroids.  Assy vids look straight forward enough, but do I need an LC
meter to measure the inductance to get it right?

I've looked at recommendations and vid reviews and the AADE LC IIB
meter looks like an adequate yet affordable piece of hardware to get
in on the ground floor of cap and choke testing.  Any comments?

nb

--
vi --the heart of evil!
Click to expand...
Do you have a 'scope and function generator? (If not I might put
those on my 'wish list' first.) If you do then I lived for years
without an LCR meter. An RC and a voltage step can give you the C.
(And John L had a neat trick of looking at the very small DC offset to
get the ESR.) Then you can resonate an LC to find L. As someone said
do a few different frequencies.

George H.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top