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Idea!! Capacitor charge in lower part of a sinus voltage Hello! I need an idea of how to charge a capacitor when a the voltage is in decay on a sinus voltage wave form ( only the positive side). The blue part of the image. I need to conserve that energy somewhere, look at the blue side of the image. I can't do it in a capacitor. It is produced by magnet over coil. PS: Its just a bad drawing, nothing is child proof, I need an idea of how to conserver that ( blue on the image ) energy somehow(eg. condenser, battery, etc) or at least much of it. if you have an oscilloscope and if you can make a video demonstrating I can pay 30-40$ I would need for you to produce a sine wave like from a generator (coil + magnet) and save the "going down sine" energy somehow, is this making any sense?