TECHNET Archives

July 2018

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
John Maxwell <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, John Maxwell <[log in to unmask]>
Date:
Wed, 18 Jul 2018 11:48:28 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (38 lines)
High dielectric constant ceramic capacitors all exhibit aging due to the crystal structure changing from ferroelectric (tetragonal or diamond) to paraelectric (cubic) structures. Higher the dielectric constant (k) and the thinner the dielectric the more rapidly the parts age or lose capacitance.

John


Sent from my iPhone

> On Jul 18, 2018, at 11:10 AM, Guy Ramsey <[log in to unmask]> wrote:
> 
> Well, I'll Be.  I cooked them at 150C for an hour and they measure 100uF
> I learned something today.
> 
>> On Wed, Jul 18, 2018 at 8:08 AM <[log in to unmask]> wrote:
>> 
>> Guy,
>> 
>> Read this and try putting the parts through their Curie point and test
>> them again.  We have seen this on some parts here.
>> 
>> https://www.johansondielectrics.com/ceramic-capacitor-aging-made-simple
>> 
>> Drew
>> 
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
>> Sent: Wednesday, July 18, 2018 7:00 AM
>> To: [log in to unmask]
>> Subject: [TN] capacitor measurement
>> 
>> I got pulled into a Receiving Inspection problem. Our test instrument, an
>> old HP 4192A impedance meter, and a newer Instek 6020 tell us that our X5R
>> capacitors are out of spec.
>> A 100uF, 10%, 6.3V capacitor measures between 25% and 30% below the
>> nominal value.  The instruments have Kelvin probes and are zero calibrated
>> at frequrency, 120Hz the test waveform is 500mV rms.
>> Does anyone have any advise?
>> 

ATOM RSS1 RSS2