How much capacitance

[Kenneth G. Gordon]

Although Paul brought up some excellent points in this 
discussion, I fear that there were many other good points 
left out of the discussion.

Tom of Hayseed Hamfest fame brought up at least one: the 
tolerance ratings of the older electrolytics.

The first one that was ignored and yet is very important is 
the internal resistance of the old vs the new ones.

 Internal resistance in the old ones was considerabley 
LOWER than modern caps. Thus, leakage current was 
higher in the older caps, and thus when they were 
discharged, they showed much lower resistance to the HV 
rectifiers.

This factor alone would result in higher in-rush current than 
similar modern caps. I=E/R. If R is lower, I is higher.

Another factor left out is that Heathkit used transformers 
which were PURPOSELY designed to limit inrush current.

See Rich Measures' site, http://www.somis.org for further 
details on this little-known fact.

I'll have more later on this subject...

Ken Gordon W7EKB

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