about charging caps with radiant energy

[sinergicus]

Hi guys ;in one of the FEG movie I saw big caps charged with radiant energy
from ssg .Bedini said ,that big caps have around 80 volts ,but is charged with hundred volts radiant energy.That big cap have across (paralleled ?) a little caps ,or something else, that allow the big 80 V capacitor to be charged with HV radiant energy.
What is that little thing hoked across to big cap and how is working to not destroy the dielectric of big 80 v capacitor , and the same time charging it with HV radiant spike...?

Can somebody enlighten me?

Thanx
Mike

[Tecstatic]

I don't know the specific circuit you speak about, but generally the following is valid.

A big electrolyte capacitor has also inductance in the leads and also the internal plates, planar or circular. This results in the impedance rising with frequency.

Radient energy is high frequency, so although the big capacitor can store a lot of charge, it can not work well at high frequencies.

On the opposite end you have surface mounted ceramic multilayer capacitors, eg. a 1206 case (12mils long 06mills wide). This capacitor has excellent high frequency properties because of its compact size, the solder connections are located on the short side.

If very low inductance/very good high frequency properties are wanted, you can get larger surface mounted capacitors where the connections are at the long side.

In a switch mode supply you get the least ripple from these capacitors, because at high frequencies the low impedance determines the ripple level.

So by adding a small low inductance capacitor to the big capacitor you get the good high frequency properties from the small cap combined with the large capacity from the big cap.

Eric