# Capacitor Power Dissipation

Discussion in 'General Electronics Chat' started by buttacup, Feb 14, 2009.

1. ### buttacup Thread Starter New Member

Feb 14, 2009
2
0
A capacitor in an AC circuit will charge and discharge with respect to the frequency of the signal voltage. Impedance in the circuit is proportional to this frequency and its capacitance. In a power supply the current is regulated through the discharge cycle. What happens to the energy when there is no place to discharge to? Just a capacitive load.....

"This means that a capacitor does not dissipate power as it reacts against changes in voltage; it merely absorbs and releases power, alternately. "

Does this statement mean that all ESR and leakage inefficiencies aside there will be no current in the primary of the transformer beyond the initial charging of the capacitor??????? If this is the case what are the considerations for capacitive loading of a transformer just the initial spike and the inefficiency resistances of the capacitor and transformer??? Is the current through the secondary still a limiting factor???

2. ### kubeek AAC Fanatic!

Sep 20, 2005
4,687
805
Except for the last question, all Yes.
What do you mean by "Is the current through the secondary still a limiting factor???"? what current, limiting what?

3. ### buttacup Thread Starter New Member

Feb 14, 2009
2
0

So you would you say the power is not returned to the hydro station?

4. ### kubeek AAC Fanatic!

Sep 20, 2005
4,687
805
Sorry but you have to draw some schematic, or explain a lot more what you are talking about. I just don´t see how some "hydro station", whatever that should be, affects a transformer with a capacitor on the secondary.

In case of power supply, you have to add the bridge rectifier to your equations.

The maximal current through secondary, and maximal voltage are the limiting factors for a transformer. But the maximal current is related to the thickness of both primary and secondary windings, so a real transformer can withstand way bigger current for a short time.