Instructables

Flashlight Without Batteries--from the book, "Haywired"

Featured

Step 1: Put capacitors in series

Picture of Put capacitors in series
First, solder a wire from the (+) on one capacitor to the (-) on the other capacitor.
nani20104 years ago
hey those are only farad capacitors or micro farad.
i got only micro once plz reply that what i sould keep
.
artemff5 years ago
I didn't quite get an idea of connecting the capacitors in series.
If one wants to increase the capacity, one has to connect them in parallel:
http://www.allaboutcircuits.com/vol_1/chpt_13/4.html

Second thing that bothers me is the using if an external battery. It would be more useful to have any small "generator" to pump energy to the capacitors.
Coil with moving core and diode rectifier is the first that comes to mind.

Good luck with your experiments :)
MikeTheMaker (author)  artemff5 years ago
I went in series to boost the voltage (each cap was only good for 2.3 volts) and I wanted more voltage to run the white LED direct (without other circuitry). You are correct that my capacitance gets cut in half when I put two in series. Charging the capacitors takes a pretty strong energy source because--in two or three minutes--you are putting in the energy that comes out over several hours. I'm going to Maker Faire with a human powered generator and a "big" bank of capacitors--if you can get out there, come by and check it out.