ferrite beads

[till]

ok, i frequently read ferrite beads should be used in IC power supply line.

some questions: why not use small inductors like http://www.reichelt.de/bilder/web/B400/!SMCC.jpg
?

and for the beads, i got some AMIDON beads http://www.reichelt.de/bilder/web/B400/T20.jpg

diameter 6,48 mm
inner diameter 3,05 mm
thick 2,44 mm
AL (µH/100Wdg): 34
MHz max.: 30

and enamelled copper wire 0,6 mm diameter.

So how many windings of wire should i make with the wire trough the bead? Or what values of those inductors of the kind package looking like resistors? Shoul the ferrite bead near to IC like the capacitors, or should it be near to power supply to filter HF coming from powerline, regulators etc. ? What about a Filter chain like 1000uF, 100R, 220uF, 100uH, 220uF,ferrite bead, 10uF+100nf at IC?

 

[Jocko Homo]

Hate to tell you this, but.........

It looks like what you have there is not a ferrite, but a powdered iron toroid, used for winding inductors.

Ferrites beads are usually specified as to what ferrite mix they are made of. Toroids for inductors are usually specified as to "max useful frequency", and uH/x turns.

A ferrite bead should be either a type 43 or 73 mix. There are a few other mixes that they are made with, but are not as common. Unless the supplier can tel you which mix, do not buy them unless you have lots of experience.


Jocko

 

[till]

Thanks for information. Its no problem, i got 10 of those "wrong" beads/torroids for free. Whatever i will do with them... I have no problem to get some ferrites with type 43,61,or 77 .

But please give me information how many windings i need, or what values for inductors, to make the power supply line for a DAC / AD1865NK.

My problem is not to get the right parts if i´m told which ones, but i have no information about values to use or a schematic to looks at.

In other words, i lack the experience you mention.

 

[Bricolo]

Jocko, I haven't found tha material used in the chokes I use
are they any good?

 

[Elso Kwak]

Ferrite Beads

Jocko, I haven't found tha material used in the chokes I use
are they any good?

Bricolo,
If look at the graphs in the paper you submitted you will see that the BL02RN2 offer excellent attenuation at "CD frequencies".
Guido Tent is suggesting BLM31A J601SN1 also from Murata. These are SMD beads. (Farnell part# 581094)
No more hints from me, remember you are the student in electronics, I am just the bloody chemist.

 

[till]

Anybody who could give me some answers?

 

[Bricolo]

Re: Ferrite Beads

No more hints from me, remember you are the student in electronics, I am just the bloody chemist.

You know I also studied chemistry 😉
I hope my teachers won't read this, but for the momment I learnt more from you and other people here on diyaudio than from them

 

[Elso Kwak]

Answers

Anybody who could give me some answers?

Hello Till,
Your coils are useless at high frequencies.

 

[Elso Kwak]

Re: Re: Judgement of Value

I hope my teachers won't read this, but for the moment I learnt more from you and other people here on diyaudio than from them

Now, is this a judgement of value on you or your teachers.....?
😕 😱

 

[till]

which coils, the SMCC ones, or the toroids Jocko allready told me are useless? What frequencies are we talking about?

- So how many windings of wire should i make with the wire trough the bead?

- Or what values of inductors is needed?

- Should the ferrite bead near to IC like the capacitors, or should it be near to power supply to filter HF coming from powerline, regulators etc.?

- What about a Filter chain like 1000uF, 100R, 220uF, 100uH, 220uF,ferrite bead, 10uF+100nf at IC?

 

[Bricolo]

Re: Re: Re: Judgement of Value

Now, is this a judgement of value on you or your teachers.....?
😕 😱

Absolutely not!
My teachers are nice, I only said that I've learnt more things here for the things I'm interested in (audio related electronics)

 

[till]

i have nothing against disussing the quality of Elso or others as a teacher in this thread, but i would much prefer to learn if these ferrites/inductors in power supply line are snakeoil or valid physics. In second case there must be some numbers in Herz we want supress, Henry the devices should have , etc.
http://www.diyaudio.com/forums/showthread.php?postid=381765#post381765

 

[Bricolo]

This has already been answeared

the coil is OK, the toroid isn't (use a ferrite bead instead)

 

[Elso Kwak]

This has already been answeared

the coil is OK, the toroid isn't (use a ferrite bead instead)

Sorry, wrong answer.

 

[Bricolo]

🙁

 

[Elso Kwak]

Last Hint

http://www.diyaudio.com/forums/showthread.php?postid=365296#post365296
and below.

 

[till]

Yes, but:
- So how many windings of wire should i make with the wire trough the bead?

- Or what values of inductors is needed?

- Should the ferrite bead near to IC like the capacitors, or should it be near to power supply to filter HF coming from powerline, regulators etc.?

- What about a Filter chain like 1000uF, 100R, 220uF, 100uH, 220uF,ferrite bead, 10uF+100nf at IC?

 

[jcx]

for good high frequency attenuation you only use 1 pass thru the bead, not "turns"

when the ends of the wire (or worse, adjacent turns) get close together they have capacitive coupling that shorts out the inductive/resistive impedance from the ferrite - check out "self-resonant frequency" for multiturn inductors

its better to use more (or larger) beads (with a hole that barely passes your wire) on a straight wire than to try to increase inductance with extra turns - some multi hole beads are made to get higher loss in a small space but the rule is still one pass of the wire thru each hole

 

[till]

ok, if they have no values i will give up and not use them, i use some 100uH coils instead.

 

[till]

Oh, thanks, some hard information, so i use a large bead with small hole , material 43, no turns, some of them on a wire.