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Re: about electronics

From john larkin <jl@glen--canyon.com>
Newsgroups sci.electronics.design
Subject Re: about electronics
Date 2026-04-28 09:22 -0700
Organization A noiseless patient Spider
Message-ID <osm1vkljfruma48ancfu6o719gjblhbot4@4ax.com> (permalink)
References (5 earlier) <10sipkr$ueq9$1@dont-email.me> <e50qukttsk01el7s3l21vaev1cokgko915@4ax.com> <10skt7b$1gnss$6@dont-email.me> <bqgvukdpqav7gpado09tg5g7lsh455q8ob@4ax.com> <10spohh$2vate$2@dont-email.me>

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On Tue, 28 Apr 2026 17:44:47 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

>On 28/04/2026 6:24 am, john larkin wrote:
>> On Sun, 26 Apr 2026 21:34:01 +1000, Bill Sloman <bill.sloman@ieee.org>
>> wrote:
>> 
>>> On 26/04/2026 4:08 am, john larkin wrote:
>>>> 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.
>>>
>>> The instant start LC oscillators are a bad idea. You can get much better
>>> timing out of a continuously running oscillator - you need two
>>> interpolation circuits rather than just one to find out where your
>>> interval started as well as where you want it to end, but the lower
>>> jitter on the continuously running oscillator makes that a better choice.
>
><snipped self-advertising>
>
>
>> There are lots of ways to make a triggered delay with XO accuracy and
>> jitter. Most involve a lot of insertion delay, and some have analog
>> s/h drift that is work to correct for.
>
>The ones that involve less insertion delay are more interesting.
>
>> Many users want minimal insertion delay.
>
>Most of them want the timing ramp to start a few nanoseconds before they 
>know they need to start it. Thiotimoline would solve that problem, if it 
>existed.
>
>https://en.wikipedia.org/wiki/Thiotimoline
>
>It can make more sense to redesign the experiment so that you can 
>control when it starts, but customers don't want to do that - they do 
>try to buy their way out of bad system design choices.
>
>> The instant-start oscillator is great in that respect.
>
>But not in others.
>
>> After it starts, we observe it for a while
>> and phase-lock it to a good OCXO but keep the timing based on the
>> trigger.
>
>Which inserts a delay.

About 3 nanoseconds. If the triggered oscillator is accurate and
low-jitter on its own, we can observe it and phase lock it at leisure.
No rush.

The HP 5359A time synthesizer used a triggered delay-line oscillator
and used a slow complex heterodyne system to phase-lock it to an OCXO.
Similar idea. But they didn't have access to fast ADCs and DACs like
we do now.

My favorite triggered oscillator uses a coaxial ceramic resonator, but
that has lots of real-world problems.

>
>>> You can't make a silk purse out of a sow's ear.
>> 
>> That's clever. Did you make that up?
>
>Like the emitter-coupled monostable, it isn't original.
>
>> Here's our benchtop DDG.
>> 
>> https://highlandtechnology.com/Product/P500
>> 
>> One nice feature is the GaN output stages that make super fast clean
>> pulses over a wide voltage range.
>
>Pity about the instant-start timing oscillator.

OK, you design a DDG and show me how.



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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