> In (through) the dielectric…. I literally blew a hole in a mason style jar with the caps at approx 70 deg F.
> In a pathetic attempt to get the most “storage” out of each cap I only had a 2” space between the top of the jar and the foil, which caused flash over.
> I then went to a “peanut butter” style jar with plastic lids and all thread.
> But every jar had a corona around the top of the foil, pretty pinkish purple, but still wouldn’t kick as anticipated.
> On Sep 6, 2016, at 6:31 AM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:
>
> On 8/1/16 12:05 AM, undisclosed recipient via Tesla wrote:
>> If they are or are not is moot…. the amount of power lost is massive…..
>> I could never eliminate the corona on the jars.
>> I had 36 “peanut butter” style jars with plastic lids which prevented flashover, but the coil still didn’t perform as well as with solid state caps.
>
> but is it dielectric loss in the glass or corona loss that is the dominant loss mechanism.
>
> microwave101.com has some data
> http://www.microwaves101.com/encyclopedias/miscellaneous-dielectric-constants
> borosilicate glass is epsilon 4.3, tan(d) of 0.0047
> soda lime glass is given as epsilon 6.0, tan(d) of 0.02 which is higher.
> http://www.microwaves101.com/encyclopedias/glass-materials
>
> comparing to PTFE which has epsilon 2.1 and tan(d) of 0.00015 to 0.0003
>
> An agilent ap note gives tan(d) (at 100 MHz!) for Polyethylene, PTFE,etc of 2E-4, fused silica at 2E-4 as well, and pyrex as 3E-3
>
> but that's at a much higher frequency, and you need to be careful... loss is usually dependent on frequency.
>
> A 1972 report
> http://www.dtic.mil/dtic/tr/fulltext/u2/746686.pdf
>
> (see page 84 for example) shows tan(d) <1E-5 for frequencies below 1 MHz.
>
> However, note also that the loss skyrockets as the glass gets hot (and starts to be more conductive). at 200C, the loss at 1kHz is >10 times worse.
>
> page 91 is a bit worse (mixed silicate glasses)... 0.005 loss tangent at 1 MHz at 21C, 8E-3 at 74C
>
>
>>> On Sep 5, 2016, at 5:50 PM, homerlea--- via Tesla <tesla@xxxxxxxxxx> wrote:
>>>
>>>
>>> Anyone know if borosilicate glass used in labs works better(less lossy) than the normal soda lime glass of regular bottles for making salt water capacitors?
>>> Jim Heagy
>>>
>>>
>
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