Re: MMC Cap choice

["Steve" <seric48-at-xxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Neil, All,

  Those axial-leaded caps, according to the voltage/frequency graph
 between the price list and the glowing description, are not rated
 for Tesla coil frequencies.

  The AC rating (450VAC) stays the same through 10KHz, but drops
 steadily from there to 90VAC at 100KHz. Not a good thing at all!

(Note to List: To see the cap data Neil's link referred to, go to

    http://rswww-dot-com

 select 'RS Stock No.' in the upper box of their search widget,
 enter '114-474' in the lower box, and press the 'Go' button )

  Steve Copeland


--- from Tesla List ---
>
>Original poster: "Neil Chambers" <Neil_Chambers-at-paragon-it-dot-com> 
>
>I am trying to source my caps for an MMC.
>
>The recommendation seems to be metalized polypropylene, but the axial
>polypropylene ones are far cheaper. Are they any use? 
>
>Here is a link to some I found:
>http://rswww-dot-com/itc/scripts/Browse.jsp?BV_SessionID=-at--at--at--at-1261021734.09738507
>22-at--at--at--at-&BV_EngineID=haljfjjlmhdbemfcfkmcggcg.0&usertype=guest&browseOID=-1004
>56322
>
>They are rated at 1500VDC and the tech. info states "A very low loss
>dielectric suitable for continuous use at high a.c. voltages. It will
>withstand high voltage, fast rise time pulses and has an excellent high
>frequency performance."
>
>I want the 0.047uF ones which are only about 35p whereas the metalized
>polyprop ones from the same firm are about £2.50 each!
>
>What do you guys think?
>
>Thanks a lot
>
>
>Neil
>