Re: an electronish puzzle

From: Ken Smith (kensmith_at_green.rahul.net)
Date: 03/25/05 

Date: Fri, 25 Mar 2005 03:56:58 +0000 (UTC)

In article <phi041165n4bvhunegkkfo0f60sne9o7pr@4ax.com>,
John Larkin <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote:
>On Tue, 22 Mar 2005 15:16:50 +0000 (UTC), kensmith@green.rahul.net
>(Ken Smith) wrote:
>
>>In article <9a4u319497u9jbn4ljfk5afjobp7oc3dq8@4ax.com>,
>>John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>>[...]
>>>So, why can't a poor engineer buy NTC surface mount ceramic capacitors
>>>anywhere? That's the real mystery.
>>
>>SMT inductors often have a NTC. How about putting one in series with the
>>capacitor?
>>
>
>
>The inductor I'm using in this oscillator, a 1008 surface-mount, has
>(apparently) a strong positive TC. All the aircore inductors I've used
>had positive TCs; I guess they just expand with temperature, and
>bigger diameter makes more L. This is only 150 nH, so a
>temperature-compensating core is probably out of the question.

I assume you are running above 100MHz. In general cores become near
useless at those frequencies. You may still be able to find some with
cores. It would be interesting to know if their tempco could be counted
on. 

-- 
--
kensmith@rahul.net   forging knowledge

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