[AMPS] Series Parallel Electrolytics & Current

[Rich Measures]

>
>
>On Sun, 27 Sep 98 18:36:26 -0800 Rich Measures <measures@vc.net> writes:
>>
>>>Hi Rich
>>>
>>>I am sure I am just missing something but what are the DIGI-KEY part 
>># for
>>>the 105 degree 470uF Caps. ......
>>
>>P10170-ND.    Thanks for the heads up, Paul.  I intended to put this 
>>in the article.  
>>>
>>>> 105† deg C rated electrolytic capacitors last much longer than 85† 
>>C
>>>rated electrolytics.  -  -   I would use 2x 24 Panasonic [Matsushita]
>>>470uF, 450v, 105† C rated units in series parallel. This would 
>>deliver
>>>about 40uF @10.8kWV.  I would use one 100k ohm, 3w equalizer resistor
>>>across each pair of paralleled 470uF units.  It is my opinion that 
>>for SSB
>>>operation, less C would work ok.  Also, I would mount the individual
>>>electrolytics on a 7mm or more-thick acrylic sheet with silicone 
>>rubber adhesive to reduce
>>>case stress.   (Digikey currently sells these caps. at c. $12.20 each 
>>in
>>>10 unit quantities.)  
>>>>
>>rong.  Current pricing is $13.85 ea.  for 10 - 99 units.
>
Carl writes:
>Identical rated caps made in the USA by CDE are available from Mouser. 
>Part # 381LX471M450A052 ( Mouser # 5985-450V470) are $11.29 ea  Qty
>10-99.
>
The rating is 85ºC.  The Panasonic capacitor is rated at 105ºC.  The price on the CDE cap. is currently $10.21 at 10 - 99 units.  .  

>These and the Panasonic are good caps but be careful of the ESR and
>ripple current ratings which are signifigantly worse than computer grade
>caps.

The Panasonic caps. are rated for ripple current in the Digikey catalog.  .  The CDE computer grade caps are not rated for ripple current in the Mouser catalog.  .  Good ripple current rating means low ESR.  



Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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