These amazing devices store an electrical charge, so it can be used later. 'Normal' capacitors usually store energy for a few seconds to help buffer power supply wobbles. Thes 'ultra' or 'super' capacitors have a much larger surface area and so can store much more energy so it is useful for longer periods.
The 10F 2.7V version can store a lot more charge, but the voltage is lower, so you need to use two in series to work with our solar panels.
You need to be quite careful with these - too high voltages will break the very thin layers within the capacitor. Do not go over the rated voltage!
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