> From:         Jinx[SMTP:joecolquitt@CLEAR.NET.NZ]
> Sent:         Tuesday, March 30, 2004 7:37 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [EE:} Measuring inductance

> I need to find an inductor 500mH-700mH for use in an audio filter,
> up to about 10kHz

> None of my regular suppliers has any inductors that go that high.
> According to info on the web, it should be possible to use a small
> transformer

> I have quite a few of these, envulturated from SMPS etc, but they
> have VA or impedance rather than inductance ratings, or have just
> a part number, so I need to find out for myself if a primary or secondary
> winding will be suitable

> Is this method going to do what I need ?

> http://et.nmsu.edu/~etti/fall96/electronics/induct/induct.html

> BTW, what is "a known resistance R between 100 S and 1 KS" ?

> A typo for omega ?

The letter S is the abbreviation for "Siemens", which is the standard unit
of conductivity, replacing the "mho". When discussing very small
resistances (less than 1 ohm), it is more convenient to use conductivity
(the reciprocal of the resistance in Ohms) since this makes the numbers
larger than 1.

100 S = 0.01 Ohm
1 KS = 0.001 Ohm

John Power

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu