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Impedance Matching

M

Mehdi Fatemi

Jan 1, 1970
0
Hi,
How can I match 120 ohm impedance to 75 ohm impedance by passive circute?

Thanks
Mehdi
 
R

Rene Tschaggelar

Jan 1, 1970
0
Mehdi said:
Hi,
How can I match 120 ohm impedance to 75 ohm impedance by passive circute?

Wideband obviously.
With a T or Pi Resistor network or perhaps with a transformer
if DC is not included.

Rene
 
L

Leon Heller

Jan 1, 1970
0
Mehdi Fatemi said:
Hi,
How can I match 120 ohm impedance to 75 ohm impedance by passive circute?

A suitable transformer.

Leon
 
T

Tam/WB2TT

Jan 1, 1970
0
Mehdi Fatemi said:
Hi,
How can I match 120 ohm impedance to 75 ohm impedance by passive circute?

Thanks
Mehdi

If it is single frequency, low power, a 1/4 wave section of RG62.

Tam
 
A

Activ8

Jan 1, 1970
0
How do you organize your links and responses (someone else, or maybe
you, just recently repeated a response from not long ago) so you can
find them quickly and not have to type the same stuff 5 or so ( ;) )
times a month?
 
J

Joerg

Jan 1, 1970
0
Mehdi said:
Hi,
How can I match 120 ohm impedance to 75 ohm impedance by passive circute?

Thanks
Mehdi
If you can tolerate the little loss, maybe a 45 ohm resistor in series
would do? This makes the 75 ohm side look like 120 ohm. I know this
sounds crude but it can work.


Regards, Joerg
 
J

John Popelish

Jan 1, 1970
0
Joerg said:
If you can tolerate the little loss, maybe a 45 ohm resistor in series
would do? This makes the 75 ohm side look like 120 ohm. I know this
sounds crude but it can work.


Regards, Joerg

That makes the 75 ohm look like 120, but doesn't make the 120 look
like 75. You can make that series resistor 73.5 ohms and parallel the
75 ohm side with 122.5 (or there abouts) and both sides will match.
 
J

John Fields

Jan 1, 1970
0
How do you organize your links and responses (someone else, or maybe
you, just recently repeated a response from not long ago) so you can
find them quickly and not have to type the same stuff 5 or so ( ;) )
times a month?

---
Usually it only takes a few minutes to find/refind a link and type a
response to a question, so I don't have anything really "organized",
per se, except for a stash of non-ASCII schematics which I've come up
with over the years for this and the other electronics newsgroups.
_BUT_ I'm working on getting my web site updated and when I'm done
there'll be an area where schematics will live (like on Jim Thompson's
site) and an area with good links and maybe a FAQ-like area with text
and graphic explanations for some of the commonly asked questions
which come up time and time again.
 
D

Doug Goncz

Jan 1, 1970
0
That makes the 75 ohm look like 120, but doesn't make the 120 look
like 75. You can make that series resistor 73.5 ohms and parallel the
75 ohm side with 122.5 (or there abouts) and both sides will match.

Thank you, Professor Popelish! I just learned something and it stuck!


Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

Read about my physics project at NVCC:
http://groups.google.com/groups?q=dgoncz&scoring=d plus
"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.
in the search box
 
J

John Popelish

Jan 1, 1970
0
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