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What circuit for an Hand Cranked Led Torch? Answered

Hi all Instructables! I follow a lot this site and now i hava a little project to do.
I want to build a Led torch that is charged using a DC motor and a couple of High Capacity Capacitors. The problem is that i'm not very good with electronics (i've made a chemistry school) but i really like it.
So, what kind of circuit i have to use for something like this?
I use a Dc motor that have about 4.5V output, the led are standard white ones, 3.5V 30mA.
Some friends told me to use an LM1086 voltage regulator that have the output with the capacitors, other say to use only a rectifier diode, other say that i have to use a Led Driver (but i think it is useful for big one, not mine...)
My goal is to make the circuit very relyable, but not impossible to make and that make the Led well balanced, good brightness/consume ratio...

Thank you!


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Best Answer 10 years ago

Did you look at this instructable?

I believe the second diode that is in series with the motor is acting as his diode to keep the capacitor from discharging thru the motor and spinning it backwards.

If you want to use a regulator the 1086 would work.  There are even versions that are set a 3.3 or 3.45 volts.


Answer 10 years ago

That, and it'd act as a charging light. Trouble with an LED is it's going to limit the capacitor voltage to generator -1.2 -ish