peak voltage

[terrakota]

hi,
I'm a little confused when and when not take in account the peak voltage,

i understand that when i use pure DC i dont need to worry about the peak voltage value but if I'm working with AC voltage like in power supply applications i must take peak value in account, my question is at what point peak voltage dissapear? or no longer exists? ie, in a power supply application that converts AC to DC and "reduce" the AC voltage u use a bridge rectifier and some capacitors, to choose the rigth capacitor filtering i need to take in account the AC voltage(ripple?) but after capacitor filtering an AC voltage not exist any more so, theres no more a peak voltage?
with pure dc voltages like batteries?.

am i right? how i deal with peak voltage or when the peak voltage dont exists any more.

please excuse my poor english

 

[Yevgenip]

Well, yes. DC doesn't have peak voltage because the voltage there is constant. This is true for batteries and constant power supplies, but in some systems there are variable DC Voltages. To "erase" AC Peak voltage you can turn it into DC. AC will always have peak voltage.