Balun

S

sthim

Guest
Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...

sthim
 
transformer

"sthim" <sthim2003@yahoo.com> wrote in message
news:b6d3605f.0308131633.496ef03@posting.google.com...
Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...

sthim
Click to expand...
 
John Popelish wrote:
sthim wrote:

Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...

sthim

A 4 to 1 balun acts as a center tapped auto transformer.

From a technologist viewpoint, alot of baluns are also based upon 1:1
Click to expand...
transformations (in differing configurations.) It seems like 1:1 transformers
tend to have wider bandwidth than direct 4:1 (impedance) transformers.

So, using a 4:1 balun configuration with a natural 1:1 impedance transformer
as a constituent, it seems to tend to perform better than a 4:1 (impedance) or
2:1 (voltage) transformer.

John
 
On 13 Aug 2003 17:33:15 -0700, sthim2003@yahoo.com (sthim) wrote:

Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...

sthim
Click to expand...
I have a PDF on this. Just email me and I will send it.

--

Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
Aurora, Ontario
 
John Dyson wrote:

John Popelish wrote:

sthim wrote:

Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...


sthim

A 4 to 1 balun acts as a center tapped auto transformer.

From a technologist viewpoint, alot of baluns are also based upon 1:1
transformations (in differing configurations.) It seems like 1:1 transformers
tend to have wider bandwidth than direct 4:1 (impedance) transformers.

So, using a 4:1 balun configuration with a natural 1:1 impedance transformer
as a constituent, it seems to tend to perform better than a 4:1 (impedance) or
2:1 (voltage) transformer.
Click to expand...
There is always the Guanella 4:1 balun to consider that has a theoretically
infinite cut off frequency.
 
The best reading I have found on these mystical items is by Jerry Sevick.
There are a few papers by him, unfortunately they are IEEE and therefore
cost an arm and a leg and a good book "Transmission Line Transformers"
published by Noble. It's a bit hard to get but worth the effort.
 
The Technical Manager wrote:
John Dyson wrote:

John Popelish wrote:

sthim wrote:

Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...


sthim

A 4 to 1 balun acts as a center tapped auto transformer.

From a technologist viewpoint, alot of baluns are also based upon 1:1
transformations (in differing configurations.) It seems like 1:1 transformers
tend to have wider bandwidth than direct 4:1 (impedance) transformers.

So, using a 4:1 balun configuration with a natural 1:1 impedance transformer
as a constituent, it seems to tend to perform better than a 4:1 (impedance) or
2:1 (voltage) transformer.

There is always the Guanella 4:1 balun to consider that has a theoretically
infinite cut off frequency.

I understand that... Before I 'studied' the subject, I was also confused
Click to expand...
(like the original poster) about the real difference between a 'transformer'
and a special configuration called a 'balun.' When I was a kid, and didn't
realize the almost subtile differences, I almost thought that the term
was gratuitious (however incorrectly.) The whole area of transmission line
transformers, traditional transformers and various configurations can be
quite interesting and enlightening !!! :).

John
 
John Dyson wrote:

The Technical Manager wrote:

John Dyson wrote:

John Popelish wrote:

sthim wrote:

Could anybody help with understanding baluns? So far I know they
transform unbalanced input to balanced output and vice-versa. Say I
have a receiver coil - one that looks like a loop and the ends are
connected to a balun. The voltages on the ends are of the same
magnitude but are 180 degrees out of phase. How do these two voltages
get combined at the output? Or does this not happen? Please let me
know...


sthim

A 4 to 1 balun acts as a center tapped auto transformer.

From a technologist viewpoint, alot of baluns are also based upon 1:1
transformations (in differing configurations.) It seems like 1:1 transformers
tend to have wider bandwidth than direct 4:1 (impedance) transformers.

So, using a 4:1 balun configuration with a natural 1:1 impedance transformer
as a constituent, it seems to tend to perform better than a 4:1 (impedance) or
2:1 (voltage) transformer.

There is always the Guanella 4:1 balun to consider that has a theoretically
infinite cut off frequency.

I understand that... Before I 'studied' the subject, I was also confused
(like the original poster) about the real difference between a 'transformer'
and a special configuration called a 'balun.' When I was a kid, and didn't
realize the almost subtile differences, I almost thought that the term
was gratuitious (however incorrectly.) The whole area of transmission line
transformers, traditional transformers and various configurations can be
quite interesting and enlightening !!! :).

John
Click to expand...
There is also a directional coupler that can be formed from two cleverly connected
conventional transformers as shown in US Patent 3,426,298 Figure 10.
 
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