Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

how to match 2.7 mH+100ohm reactance to 8 ohms?

Status
Not open for further replies.

treehugger

Member level 2
Joined
Oct 23, 2005
Messages
44
Helped
3
Reputation
6
Reaction score
0
Trophy points
1,286
Activity points
1,705
what is the wisest way of matching 2.7mH+100ohm reactance to 8ohms?
at 80kHZ?

thanks.

Added after 9 minutes:

ofcourse, without using inductors in the milli henries range.
 

You can either use an inductance with two capacitors or a transformer and a capacitor, I don't think there is another option.
 

FvM said:
You can either use an inductance with two capacitors or a transformer and a capacitor, I don't think there is another option.

yes there is!

using the 2.7mH as an autotransformer in boosting fashion, and a 1.4nF capacitor.

i asked this question to see if anybody is aware of this trick, and my head is still not very clear about this solution..:

you are using the 7th winding as a tap and the rest 297 windings make it up real close to 2.7 mH. the problem is that 7 windings make up so little inductances and how come it doesnt degrade the voltage coming out of 8 ohms, its a mystery for me.

let me also upload a diagram. i am awaiting for your comments.

Added after 7 minutes:

here is the matching circuitry

port2 is 100ohms
 

0.5 ohms of resistance is included to model the wire resistance of the 7 windings.
 

Since the Q of the resulting circuit is sufficiently high, you can use either an inductive or capacitive tap (2 capacitors in series, feeding in parallel with one cap).

The voltage ratio for matching (as in the case of a transformer), would be SQRT( 100/8 )=3.53 .
So for a N turn coil, the tap will be made at n=SQRT(8/100)*N=0.28*N.
For N=300 turns, n=84 turns, a lot more than you said. The wire resistance is not critical, and the inductance won't be too low.
 

yes there is!
using the 2.7mH as an autotransformer in boosting fashion, and a 1.4nF capacitor.

allowing the impedance to be an autotransformer is a bit different from defining 2.7 mH as a reactance to match width? Or, I could say, that exactly is using a transformer and a capacitor.

To my opinion, you should ask real questions rather then saying "haha, there's a trick" without disclosing the conditions. Or do as you like, but be aware that forum members may remember you when you ask for real help.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top