Re: tiny inductor with every bypass cap?

Paul Keinanen wrote:
> On Sat, 21 Jun 2008 15:25:38 -0700 (PDT), bill.sloman@[EMAIL PROTECTED]
 wrote:
> 
>> On Jun 22, 5:52 am, Paul Keinanen <keina...@[EMAIL PROTECTED]
> wrote:
> 
>>> Are you sure that these are ordinary inductors or just a wire through
>>> a ferrite bead?
>>>
>>> While the ferrite will increase the inductance, a suitable ferrite
>>> material is also quite lossy at higher frequencies, reducing the risk
>>> for unwanted resonances with the capacitors.
>> Sadly, you can't rely on this. I've had to put little resistors in
>> series with ferrite bead to kill a resonance - admittedly at a few
>> hundred kHz, where the bead doesn't look that lossy.
> 
> It would be quite hard to find material that would be lossy at such
> low frequencies. For instance materials listed at
> http://www.fair-rite.com/newfair/materials.htm
start at 1 MHz
> (material 31), while the common material 73 have significant losses
> only above 10 MHz.
> 

I am lossy at low frequencies. Met my wife at an ultrasound company and 
she was quited stunned that my body would absorb even 3.5MHz to the 
point where she couldn't get a decent ultrasound image. Never seen it 
this bad before. She married me anyway.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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