Adjust inductance for antenna with capacitor

Status
Not open for further replies.
F

F-Moura

Junior Member level 2
Joined
Sep 18, 2013
Messages
23
Helped
3
Reputation
6
Reaction score
3
Trophy points
3
Visit site
Activity points
201
Hello all,

so, maybe this is a simple question, but I dont know for where start.

I have a electronic that need 47uH, 134.5kHz to work well. I only have a 49uH coil.
I read that I can use a capacitor to reduce inductance, but how calculate the value for it?

I can use impedance relation?

I´m starter with RF technology, so any help is much.


Regards.
 

Hi tony,

I use Series 2000 Micro Reader by Texas Instruments.
link: https://www.ti.com/product/RI-STU-MRD2?keyMatch=RI-STU-MRD2&tisearch=Search-EN

When I said coil, I meant antenna, sorry for this.
The Microreader need a 47uH antenna to work, and I did it, but now, I need use a antenna of 49 uH, for this I want use other passive components to make 49uH work with 47uH.

<a title="antenna.png" href="http://obrazki.elektroda.pl/3828776300_1403095611.png"><img src="http://obrazki.elektroda.pl/3828776300_1403095611_thumb.jpg" alt="antenna.png" /></a>

Regards
 

I suggest to read the reader's reference manual, chapter 5.2 Adapting the Inductance Range. Oops!
 

work out the reactance of your coil at its operating frequency (Xl = 2 X PI X L X F) = Xml, repeat for the specified coil (Xsl). If you have done it correctly subtracting Xsl from Xml should give you a figure (Xtoo much). You need a capacitor whose reactance at the operating frequency equals Xtoo much and put it in series with your coil. (Xc = 1/2 X PI X F X C).
Frank
 

Hello guys,

sorry for disappearing.
Using LC ressonance formula I solved easily.

FvM, I no find the book that you talk about. Can you give the full name and author?
If someone have tips of bibliography about RF, I´m grad with suggestions.

Tnx for all.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…