Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.electronics.design > #446833

Re: testing NTC caps

Show all headers | View raw

On 2/8/2017 10:57 AM, Phil Hobbs wrote:
> On 02/08/2017 11:49 AM, John Larkin wrote:
>> On Wed, 8 Feb 2017 15:12:08 +0000, Clive Arthur
>> <cliveta@nowaytoday.co.uk> wrote:
>>
>>> On 07/02/2017 23:36, John Larkin wrote:
>>>>
>>>>
>>>> We special-ordered a reel (4000 pieces) of NTC caps from Capax. They
>>>> are 0805, 3.3 pF, N4700. 23 cents each.
>>>>
>>>> I figured I should test them. I made an oven out of a roll of solder,
>>>> with the cap and a thermocouple inside.
>>>>
>>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/NTC_Setup.JPG
>>>>
>>>> It has a nice long thermal time constant. I started with a heat gun to
>>>> get it to 50C, covered it with a cloth, and took data slowly as it
>>>> cooled. Near room temp, a spritz of freeze spray into the solder coil
>>>> cooled it down, and then I took data as it slowly warmed up.
>>>>
>>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/NTC_Data.JPG
>>>>
>>>> The measured tempco is close to -7000, but that's OK. I'm going to
>>>> compensate a 600 MHz coaxial ceramic resonator oscillator, with this
>>>> cap and a series NPO padder, so too-high tempco is OK.
>>>>
>>>> It would be great to have a very small benchtop oven, peltier
>>>> hot/cold, to test small parts or circuits.
>>>>
>>>>
>>> I use a vacuum flask with wadding in the neck.  I use a small aquarium
>>> bubbler pump to pump air through silicone tubing via a power resistor
>>> (one with a cooling tube through the middle) through the wadding to the
>>> bottom of the flask.  A cheap Chinese PID controller and solid state
>>> switch to heat the resistor closes the loop.
>>>
>>> It's nice and even, low power and can be left on for days.
>>>
>>> Cheers
>>
>> I'd like to go from 0 to maybe 80C. I guess the ideal oven would be a
>> small box that I can put my circuit inside, that would ramp slowly
>> from high to low temp. If I don't want to bother to automate the
>> measurements, I could use a kitchen timer to alert me every, say, 10
>> or 20 minutes to walk over to my bench and take my data. These
>> measurements are better if the temperature changes slowly, and that
>> makes this sort of thing tedious.
>>
>> Our big oven will sweep temp, and even can be remotely controlled, but
>> it's a big deal to get wires in and out of the chamber, from DUT to
>> instruments. It's great for big-deal automated measurements of whole
>> products, with custom software.
>>
>>
>>
>
> I have a beautiful Extech 3-channel thermocouple data logger that writes
> to an SD card.    If it had a couple of ordinary ADC inputs, that would
> be about perfect, but alas.
>
> Cheers
>
> Phil Hobbs

What happened to your Labjack?

Back to sci.electronics.design | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

testing NTC caps John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-07 15:36 -0800
  Re: testing NTC caps Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-07 15:41 -0800
  Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-07 19:40 -0500
    Re: testing NTC caps John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-07 17:18 -0800
      Re: testing NTC caps "tom" <tmiller11147@verizon.net> - 2017-02-08 00:21 -0500
        Re: testing NTC caps John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-08 08:41 -0800
      Re: testing NTC caps "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-02-08 02:41 -0500
    Re: testing NTC caps bill.sloman@ieee.org - 2017-02-07 19:15 -0800
  Re: testing NTC caps Clive Arthur <cliveta@nowaytoday.co.uk> - 2017-02-08 15:12 +0000
    Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 11:47 -0500
      Re: testing NTC caps Clive Arthur <cliveta@nowaytoday.co.uk> - 2017-02-08 16:56 +0000
        Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 12:04 -0500
    Re: testing NTC caps John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-08 08:49 -0800
      Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 11:57 -0500
        Re: testing NTC caps John S <Sophi.2@invalid.org> - 2017-02-08 13:02 -0600
          Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 16:14 -0500
            Re: testing NTC caps John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-08 13:28 -0800
      Re: testing NTC caps Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 11:40 -0800
      Re: testing NTC caps Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-02-08 18:08 -0500
  Re: testing NTC caps Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 09:29 -0800
  Re: testing NTC caps Robert Baer <robertbaer@localnet.com> - 2017-02-08 21:45 -0800
    Re: testing NTC caps John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-09 11:20 -0800
      Re: testing NTC caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-09 14:29 -0500
        Re: testing NTC caps Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-09 22:52 +0000
          Re: testing NTC caps pcdhobbs@gmail.com - 2017-02-09 16:58 -0800
            Re: testing NTC caps Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-10 09:01 +0000
            Re: testing NTC caps John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 11:39 -0800
              Re: testing NTC caps Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-02-10 22:49 -0500
        Re: testing NTC caps krw@notreal.com - 2017-02-09 21:18 -0500
          Re: testing NTC caps pcdhobbs@gmail.com - 2017-02-09 18:54 -0800
            Re: testing NTC caps Clifford Heath <no.spam@please.net> - 2017-02-10 14:18 +1100

csiph-web