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From: Jan Panteltje on 11 Aug 2010 10:35

A cheap (< 10 $) very accurate LC meter with RS232 interface.
http://panteltje.com/panteltje/pic/lc_pic/

All credit goes to somebody else (actually a lot of people) for this design.
I merely simplified it some more :-)
It seems to be very accurate, and is most useful if you are winding your own inductors
or working with RF and extremely small capacitors, a few pF is no problem for this.
It cancels out any lead capacitance in your test leads...
Have fun :-)


From: Tim Wescott on 11 Aug 2010 11:51
On 08/11/2010 07:35 AM, Jan Panteltje wrote:
>
> A cheap (< 10 $) very accurate LC meter with RS232 interface.
> http://panteltje.com/panteltje/pic/lc_pic/
>
> All credit goes to somebody else (actually a lot of people) for this design.
> I merely simplified it some more :-)
> It seems to be very accurate, and is most useful if you are winding your own inductors
> or working with RF and extremely small capacitors, a few pF is no problem for this.
> It cancels out any lead capacitance in your test leads...
> Have fun :-)

Interesting. It only measures at one frequency, and that frequency is
the one that the components pick, so it's not necessarily good for
characterizing, say, capacitive reactance at a given frequency.

But for less than $10 out of a well-stocked junk box, I don't know if I
should argue.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
From: Phil Hobbs on 11 Aug 2010 11:54
Tim Wescott wrote:
> On 08/11/2010 07:35 AM, Jan Panteltje wrote:
>>
>> A cheap (< 10 $) very accurate LC meter with RS232 interface.
>> http://panteltje.com/panteltje/pic/lc_pic/
>>
>> All credit goes to somebody else (actually a lot of people) for this
>> design.
>> I merely simplified it some more :-)
>> It seems to be very accurate, and is most useful if you are winding
>> your own inductors
>> or working with RF and extremely small capacitors, a few pF is no
>> problem for this.
>> It cancels out any lead capacitance in your test leads...
>> Have fun :-)
>
> Interesting. It only measures at one frequency, and that frequency is
> the one that the components pick, so it's not necessarily good for
> characterizing, say, capacitive reactance at a given frequency.
>
> But for less than $10 out of a well-stocked junk box, I don't know if I
> should argue.
>

Cute. I still prefer my Smart Tweezers, but they cost $400!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
From: Grant on 11 Aug 2010 11:59
On Wed, 11 Aug 2010 14:35:30 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote:

>
>A cheap (< 10 $) very accurate LC meter with RS232 interface.
> http://panteltje.com/panteltje/pic/lc_pic/
>
>All credit goes to somebody else (actually a lot of people) for this design.

Small world, Phil Rice was one of my lecturers at LTUB a decade ago :)

My final year 'major project' is still up (9 years later) on that machine,
web based info-sys renders properly in modern browsers too.

>I merely simplified it some more :-)
>It seems to be very accurate, and is most useful if you are winding your own inductors
>or working with RF and extremely small capacitors, a few pF is no problem for this.
>It cancels out any lead capacitance in your test leads...
>Have fun :-)
>
Another one to keep in mind for later :)

Grant.
From: Joel Koltner on 11 Aug 2010 14:19
"Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message
news:i3ucfp$tsq$1(a)news.albasani.net...
> It seems to be very accurate, and is most useful if you are winding your own
> inductors
> or working with RF and extremely small capacitors, a few pF is no problem
> for this.

Have you tried it with any, e.g., 0805 100nH or smaller inductors? These
often have markedly difference impedances at, e.g., the VHF or UHF frequencies
you'd typically use them at than the audio or LF frequencies that most testers
use; I usually end up using a network analyzer to take a look at what their
impedance "really" is.

Definitely a nice little device!

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