Is there a difference between a RF choke and a RF coil ?

[John Popelish]

George wrote:

Maybe. An RF coil can be part of many different circuit functions,
but an RF choke is almost always a decoupling mechanism (to keep RF
out of a DC supply and vice versa).

--
John Popelish

 

[petrus bitbyter]

"George" <nospam@mindspring.com> schreef in bericht
news9ivq09dhr5dkpgktuk1r9hod2873nk33r@4ax.com...
Well,

A choke is a coil, but a coil is not necessarily a choke.

petrus bitbyter


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[Rich Grise]

On Fri, 03 Dec 2004 10:15:19 +0000, petrus bitbyter wrote:

"George" <nospam@mindspring.com> schreef in bericht
news9ivq09dhr5dkpgktuk1r9hod2873nk33r@4ax.com...


Well,

A choke is a coil, but a coil is not necessarily a choke.

I was within an RCH of posting just this, but I got to thinking - other
than on a carburetor, is there a choke that's _not_ a coil?

Thanks,
Rich

 

[Steve Evans]

On Thu, 02 Dec 2004 22:03:50 -0500, John Popelish <jpopelish@rica.net>
wrote:

George wrote:

Maybe. An RF coil can be part of many different circuit functions,
but an RF choke is almost always a decoupling mechanism (to keep RF
out of a DC supply and vice versa).

Yes. I guess a choke differs from a 'common coil' only inasmuch as its
impedance to RF signals is very high (lots and lots of turns).

--

Fat, sugar, salt, beer: the four essentials for a healthy diet.

 

[John Popelish]

Steve Evans wrote:

On Thu, 02 Dec 2004 22:03:50 -0500, John Popelish <jpopelish@rica.net
wrote:

George wrote:

Maybe. An RF coil can be part of many different circuit functions,
but an RF choke is almost always a decoupling mechanism (to keep RF
out of a DC supply and vice versa).

Yes. I guess a choke differs from a 'common coil' only inasmuch as its
impedance to RF signals is very high (lots and lots of turns).

Yes. The important feature of a choke is its impedance at some design
frequency. It isn't always important that it look inductive. It may
be close to self resonant. As long as it blocks passage of much
current at the desired frequency, it will keep that frequency from
getting across that boundary. Other coils may be much more
constrained, because their Q and actual value of inductance take part
in a resonance with other components. Or their mutual inductance to
another coil may be important.

--
John Popelish

 

[Terry]

George wrote:

Maybe. An RF coil can be part of many different circuit functions,
but an RF choke is almost always a decoupling mechanism (to keep RF
out of a DC supply and vice versa).

The reactance or impedance of an inductance is dfirectly proportional to

frequency. So at RF the choke is chosen to block or minimize the flow of
electrical energy.
Therefore I respectfully suggest that a choke is more of a 'blocking'
device.
The word 'decouple' IMHO is more suggestive of 'by-passing' or allowing
electrical energy to flow; as in the manner of say a cathode decoupling
capacitor.

 

[John Popelish]

Terry wrote:

George wrote:

Maybe. An RF coil can be part of many different circuit functions,
but an RF choke is almost always a decoupling mechanism (to keep RF
out of a DC supply and vice versa).

The reactance or impedance of an inductance is dfirectly proportional to
frequency. So at RF the choke is chosen to block or minimize the flow of
electrical energy.
Therefore I respectfully suggest that a choke is more of a 'blocking'
device.
The word 'decouple' IMHO is more suggestive of 'by-passing' or allowing
electrical energy to flow; as in the manner of say a cathode decoupling
capacitor.

We agree on the purpose. we have different preferences for
descriptive terms. I have no problem thinking of a blocking device as
a decoupling mechanism. Decoupling involves either shunt or series
elements or both.

--
John Popelish