hi
i wonder if someone can help me answer this question
how can a capacitor charge in the negative half cycle of the alternating sinusoidal voltage
we usually see this case in the pulse generator using a diac. the output is a series of positive and negative pulses
A capacitor only needs a potential difference to charge irrespective of the polarity. All capacitors except electrolytic ones can be charged at any polarity, the electrolytic ones blow up not because of the storage of charge but because of the electrolyte. And so u will always find mylar or ceramic capacitors in diac circuits or any power circuit in general
Yes, He is right.
The non-polar capacitors can work in all circuits, but electrolytic ones may be used only in constant polar situations...unless they may explore !
Cheers.
Every capacitor has a max voltage rating, given by the manufacturer, above which it should not be used. The voltage rating depends upon the type (dielectric constant ) and thickness of the dielectric medium. Electrolytes and paper have much lower dielectric constants than ceramic or mylar. Similarly, The thicker the dielectric, more voltage it can handle.. However, from ur studies u would know that increasing the thickness of the dielectric also decreases the capacitance.. so the area of the plates has to be increased proportionally. This is another advantage of ceramic and mylar capacitors, both of the materials have such high dielectric constants that they can withstand very high voltages at a considerably small thickness, while electrolytic capacitors get ridiculously big at high voltages.
Hi.
I should confirm fsahmed another time.
He has good information on capacitors, and he almost said anything about Cap.s and the effect of higher voltages on their sizes.
You may use ceramic or mylar capacitors for your higher voltage applications.
As mentioned earlier, Cap is a non-polar device. So in positive half cycle it has a positive electric field( take any reference) and in negative half cycle it has a negative electric filed.
Electric field is what holds the charge and hence voltage.
If u wish to store more charge, usee cascading.
Every cap has a voltage limit!