DC or AC in Doorknob capacitor

[Sparky_s]

Can a Doorknob capacitor be charge using High Voltage DC?
I don't know if I must to use AC Electricity.

Power Source: 3,5KV 9mA DC

Capacitors I have:
33pF 10kV 40kVAR Doorknob Capacitor

 

[Nigel Goodwin]

Capacitors can only be charged with DC.

 

[Sparky_s]

All kind of capacitors can be charged only with DC?

I ask you this question because I have seen this circuit:
**broken link removed**

And it seems that the capacitor is being charged with AC, instead with DC. Of course, there is a spark-gap and I don't know if the sparkgap has something to do with that.
Can someone explain if the capacitor is being charged with DC or AC?

 

[Nigel Goodwin]

All kind of capacitors can be charged only with DC?

I ask you this question because I have seen this circuit:
**broken link removed**

And it seems that the capacitor is being charged with AC, instead with DC. Of course, there is a spark-gap and I don't know if the sparkgap has something to do with that.
Can someone explain if the capacitor is being charged with DC or AC?

The capacitor isn't 'been charged', it's used to transfer AC - as a coupling capacitor.

 

[crutschow]

AC applied across a capacitor will alternately charge and discharge the capacitor twice each AC cycle, once positively and once negatively.

If by "charge" you mean charge the capacitor to some voltage level and maintain the charge, then you need to use DC.

 

[Sceadwian]

Actually it's being both charged and discharged at the frequency of the AC signal, if you were to remove the AC signal at the peak of the waveform the capacitor would remain charged, this is how diode rectifiers are used to turn AC into DC.