Re: about electronics

From	john larkin <jl@glen--canyon.com>
Newsgroups	sci.electronics.design
Subject	Re: about electronics
Date	2026-04-25 11:08 -0700
Organization	A noiseless patient Spider
Message-ID	<e50qukttsk01el7s3l21vaev1cokgko915@4ax.com> (permalink)
References	(1 earlier) <10sg86t$7i9b$1@dont-email.me> <q8anukp7uj4eel3lk14mhtjhh4n9kicg94@4ax.com> <10shi71$j3f6$2@dont-email.me> <h0mpuk54ttjflpd3ghulvq6kdbfq2kti9o@4ax.com> <10sipkr$ueq9$1@dont-email.me>

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On Sun, 26 Apr 2026 02:20:43 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

>On 26/04/2026 1:14 am, john larkin wrote:
>> On Sat, 25 Apr 2026 15:07:29 +1000, Bill Sloman <bill.sloman@ieee.org>
>> wrote:
>> 
>>> On 25/04/2026 3:38 am, john larkin wrote:
>>>> On Fri, 24 Apr 2026 10:10:53 -0700, Buzz McCool
>>>> <buzz_mccool@yahoo.com> wrote:
>>>>
>>>>> On 4/24/2026 8:55 AM, john larkin wrote:
>>>>>> Summary: very few people understand electronics.
>>>>>
>>>>> Edit: Very few people understand electronics as well as you.
>>>>>
>>>>> A few years ago you had some posts with typical interview questions you used.
>>>>> I collected these and sent them to my now freshly minted EE child who will
>>>>> be starting work next month. So don't think that people aren't listening.
>>>>
>>>> I hope your kid understands electricity. Most ce/ee grads don't, and
>>>> AI may make them into grocery store clerks.
>>>
>>> Probably not. AI is essentially mindless plagiarism.
>>> It gets stuff right about 90% of the time, rather like junior engineers,
>>> but needs to be backed up by people with deeper understanding
>>>
>>>>> If you have more pearls of wisdom to share, please do. Years ago Phil shared
>>>>> an article about how the front page of ceramic cap datasheets are a pack of
>>>>> lies, which was very revealing to me. Even now in the 4th quarter of my career
>>>>> I want to understand more about electronics.
>>>>>    
>>>> Ceramic caps are awful. Buy a 22uF 10v cap and you might get 3 uF at
>>>> 10v.
>>>
>>> Ceramic caps can be voltage dependent - but it does depend a lot on the
>>> actual ceramic. Reading the data sheet carefully can be informative.
>> 
>> It's rare for a ceramic cap data sheet to even mention the cap fallout
>> with voltage, much less quantify it.
>> 
>>> NPO ceramics are about as good as it gets. Ceramics with higher
>>> dielectric constants offer more - but less predictable - capacitance.
>> 
>> NPOs are great, but only come in small values.
>
>That's what I just said.
>
>>> https://en.wikipedia.org/wiki/Ceramic_capacitor
>>>
>>> does talk about this. Class 1 ceramic capacitors can be very stable.
>>> Class 2 offers more capacitance but less stability, and Class 3 offers
>>> loads of capacitance in a small package but it can vary a great deal.
>>> John Larkin doesn't seem to read data sheets in detail, and he may have
>>> bought a class 3 capacitor for a Class 2 application.
>> 
>> Classes, and categories like Z5U, are very crude. One has to test caps
>> when it matters, and then hope one can buy consistent parts.
>
>Crude they may be, but you didn't even mention that they existed.
>
>> We do buy big reels of custom-mixed caps with defined behaviors and
>> tempcos. I had Capax make us 5000 pieces of 3.3 pF 0805's, with -4700
>> ppm/degC tempco. They came out close. We have a lifetime supply.
>
>That implies more technical expertise than you exhibited above. Did one 
>of your customers spell out the details, or that pesky Ph.D. that you fired?

Neither. I use the NTCs to temperature compensate my instant-start LC
oscillators. FR4 has a radical positive TC. I typically wind up with a
parabolic frequency tempco, flat around 35c.

Most things work like that. Compensate the first-order term, and
what's left is mostly second-order.


John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics

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about electronics john larkin <jl@glen--canyon.com> - 2026-04-24 08:55 -0700
  Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 02:14 +1000
    Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-24 09:39 -0700
      Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 03:32 +1000
        Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-24 10:46 -0700
          Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 14:44 +1000
            Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 08:03 -0700
              Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 02:28 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 10:56 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 21:27 +1000
              Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 21:11 +1000
              Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 21:16 +1000
              Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 21:50 +1000
          Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-04-25 17:52 +0000
            Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 11:17 -0700
              Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-04-26 17:12 +0000
        Re: about electronics someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-04-26 05:45 +0000
          Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-26 03:29 -0700
          Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 20:55 +1000
            Re: about electronics Someone <864c855e3d64399dc06fa30ebb75526c2c2e73db7216b16a3d4cf03e8a52ec3b@example.com> - 2026-04-28 20:15 +0000
              Re: about electronics Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-04-28 16:39 -0400
                Re: about electronics someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-04-30 05:30 +0000
                Re: about electronics Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-04-30 11:19 +0000
                Re: about electronics someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-05-05 18:15 +0000
                Re: about electronics Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-05-05 19:10 +0000
          Re: about electronics Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-04-26 12:53 +0000
          Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-26 07:57 -0700
            Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-27 01:33 +1000
      Re: about electronics Someone <864c855e3d64399dc06fa30ebb75526c2c2e73db7216b16a3d4cf03e8a52ec3b@example.com> - 2026-04-28 20:15 +0000
        Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-29 14:36 +1000
  Re: about electronics Buzz McCool <buzz_mccool@yahoo.com> - 2026-04-24 10:10 -0700
    Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-24 10:38 -0700
      Re: about electronics Buzz McCool <buzz_mccool@yahoo.com> - 2026-04-24 11:22 -0700
      Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 15:07 +1000
        Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 08:14 -0700
          Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 02:20 +1000
            Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 11:08 -0700
              Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 21:34 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-27 13:24 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-28 17:44 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-28 09:22 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-29 03:24 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-28 18:58 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-29 14:27 +1000
  Re: about electronics bitrex <user@example.net> - 2026-04-24 23:20 -0400
    Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-04-24 21:50 -0700
      Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-25 08:26 -0700
      Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-04-25 17:53 +0000
        Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-04-25 11:34 -0700
          Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-04-26 16:51 +0000
  Re: about electronics someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-04-26 05:45 +0000
    Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-26 03:39 -0700
      Re: about electronics Buzz McCool <buzz_mccool@yahoo.com> - 2026-04-28 15:38 -0700
        Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-04-28 15:57 -0700
          Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-28 19:07 -0700
          Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-29 10:39 -0700
            Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-04-30 22:43 +1000
              Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-30 07:19 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-05-01 00:41 +1000
            Re: about electronics JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-30 15:54 +0100
              Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-30 09:27 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-05-01 03:26 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-30 11:38 -0700
                Re: about electronics JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-30 18:45 +0100
                Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-04-30 13:00 -0700
                Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-05-01 21:24 +0000
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-05-02 16:27 +1000
                Re: about electronics john larkin <jl@glen--canyon.com> - 2026-04-30 11:40 -0700
          Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-05-03 14:35 -0700
            Re: about electronics john larkin <jl@glen--canyon.com> - 2026-05-03 14:41 -0700
            Re: about electronics joegwinn@comcast.net - 2026-05-03 19:54 -0400
              Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-05-03 17:53 -0700
                Re: about electronics joegwinn@comcast.net - 2026-05-04 19:54 -0400
                Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-05-04 17:33 -0700
                Re: about electronics joegwinn@comcast.net - 2026-05-05 13:35 -0400
                Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-05-05 14:08 -0700
                Re: about electronics Nioclás Pól Caileán de Ghloucester <thanks-to@Taf.com> - 2026-05-05 21:29 +0000
                Re: about electronics Don Y <blockedofcourse@foo.invalid> - 2026-05-05 14:43 -0700
                Re: about electronics Bill Sloman <bill.sloman@ieee.org> - 2026-05-06 15:58 +1000

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