smiles said:
Thanks for your reply, I been said that but the thing make me feel vague is "And then discharge them at a very fast rate (aka - high frequency, even if just one cycle)."
Could you explain me more about this, thanks !!!
High frequency - as you indicated in your post - can be a single cycle - right?
And we know frequency is the inverse of time - right?
Time = 1/F
Larger frequency = lower Time
lower frequency = larger time
Still with me?
Simple RC time constants:
Time = Resistance * capacitance
https://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=31
Note how the RC time is proportional to the R.
Lower R = shorter Time
Higher R = longer time
and
Current = Volts / Resistance.
http://en.wikipedia.org/wiki/Ohm's_law
lower R = higher Amps.
higher R = lower amps
So...
a slower charge time = higher R = lower charge current
a faster discharge time - lower R = higher discharge current.
For charging, we use an actual resistor to slow down the charge time and use lower current to charge the caps.
For discharging - the 'R' is now the X-RAY transmitter - think of it like a very low resistance for when we discharge the caps.
How do we use a different resistance for charge and discharge?
Easy, a relay (a relay is a type of switch - right? - Like shown in the java applet in the first link I have above.)
So we use a lower current to charge the caps at the cost of more time, and achieve a very high current when we discharge the caps into the X-RAY transmitter, but only for a very short time (aka high frequency).
Note: I have drastically over simplified the concept - I imagine the actual x-ray machine is using a high frequency voltage multiplier to charge the caps to the 350V
Re:
https://en.wikipedia.org/wiki/Voltage_multiplier
edit: I intentionally avoid mentioning that at first, as to not confuse the multiple use of 'high frequency' that can apply in this machine you have - which gets into much more difficult to explain concepts in AC theory. But all of the above can still apply, just not necessarily *exactly* to the particular machine you have those caps in. Depends on its design and the X-Ray transmitter used. /edit.