Picture of Supercapacitor USB Light
For those who never heard about supercapacitor, you can check for more info about supercapacitor here. Supercapacitor is basically a capacitor with very high capacity, and the capacity rating is normally around few Farads. With the “super” capacity, it basically can store a lot of charge, and I am going to use the “super” capacity to store charges for a 5mm LED. Let’s see how long will the 5mm LED last.
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Step 1: Components Needed

Picture of Components Needed
The components you will need for this project is basically a supercapacitor (I am using 5.5V 0.1F supercapacitor which I bought from Farnell), a White LED, a 1K Ohm resistor and a USB male connector (I get this from an broken pendrive).

Step 2: Supercapacitor Polarity

Picture of Supercapacitor Polarity
Make sure you know the polarity of the supercapacitor, or refer to its datasheet

Step 3: Soldering

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The first step is to cut the 2nd and 3rd pin of the USB male connector, we will need only the 1st and 4th pin (5V and 0V pin).

Then solder the negative pin of the supercapacitor to the 4th (0V) pin of the USB male connector.

Now, try to connect the positive pin of the supercapacitor to the 1st pin (5V). For the connection I am using a resistor leg.

Step 4: Soldering

Picture of Soldering
Next, connect the positive pin of the White LED to the 1st pin (5V) of the USB male connector.

Finally, connect a 1K resistor from the negative pin of White LED to the 4th pin (0V) of the USB male connector.

Step 5: Schematic

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Please check the diagram below for the complete schematic. You are actually free to use higher Farad supercapacitor, but voltage rating must be larger or equal to 5V, and you can have your creative way to connect all the components together.

Step 6: Testing

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Now, plug it to your computer for around 10-30 seconds to charge up the supercapacitor.

You should see the White LED turned on (if it doesn’t turned on, there are some mistake in the connection), then after 10-30 second, you can unplug it and you should have around 10 minutes of the LED light.

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it would be great to put a couple of supercap in paralel to get a larger capaticance, and you forgot that if not healty for supercaps to charge them with unlimited current, the USB port has a limmited current to 500mA , and it would be great to add some PWM to circuit, it's more efficiant than a ressistor, besause the ressistor turns the unused energy to heat, so the NE555 SMD in C-mos used like PWM would be perfect for this project

PS, there are supercap that has a capaticanse of 7F but only 2V , add a hand generator to charge it and a 1,5V LED driver and ingoy your hand rechargeable flash light.

sorry for bad english, I'm from Serbia :)

I am from the US, and your English is better than most Americans'. Please do not apologize. :-)

I know of a company that makes 150F supercapacitors at 1.5-2vdc for use in industrial applications
I never heard that much of capacitance before. 150F supercapacitors, that's monster size... I wonder what kind of circuit will need that amount of capacitance.
resently maxwell tecnologies came out with a 3000F 2.7V Boost cap! :D it's now avalible on the consumer market the only place i know that sells these is electronics goldmine and mouser there very nice capacitors and thier about 20-30$ on avrage each but if you get lucky you can get them for 10$!!! oh an answer to your qestion, these high capacitence capacitors are used in green energy, energy storage, and well as hybird cars :D
thank you for your answer :)
I just made mine and it is so awesome!! I did add a modify it though, instead of using just one LED I used two, and used a slide switch to alternate between them.
bustatech (author)  buckminsterfullerene3 years ago
Very nice! You can use "3 step slide switch" (not sure the exact name of the slide switch with 3 steps), and you can choose to ON LED1, ON LED2, or OFF both LEDs.
3 stage slide switches really hard to get a hold of, I've looked several times. Do you know anywhere good? has them but all I could find were ON-ON-ON, I didn't see any ON-ON-OFF switches there.
Just don't connect the third input and it's the same thing.
wow, they are cool!
could you show me how to make this, thanks :)
can have the circuit you made to have the design
beju05066 months ago

Hi! I wanted to say thank you for posting this! I merged this idea with another one I came across here to make something new:
Just wanted to say thanks again for the inspiration! :)

awl18 months ago
-- We are manufacturer
Peboz Products Limited is a dynamic, young but experienced manufacturer, focusing on innovative energy efficient and latest LED technology products. Headquarter based in Hong Kong, we have an operational office set up at Shenzhen and a manufacturing plant locates at Dongguan China.
ryanmercer3 years ago
Emergency USB back-up lighting :) although always on.
just add a micro switch in between capacitor and led loollolol
mittu gat2 years ago
hi what if i use 1.0F Capacitor ,,, will i get longer pereiod of discharge and what is the difference?
progman323 years ago
Pretty cool idea! One possible issue for people duplicating this. Depending on how fast your supercapacitor can charge, you may end up overdrawing on your USB port if the capacitor is fully discharged. Won't hurt anything, but the port will shut off power to protect itself, thus not charging your light. You may want to include a low-value resistor (maybe 1-3 ohms) between the cap and VCC if you find your light won't charge at all or just blinks once when you plug it in.
Absolutely.. that much of capacitance will initially make nearly short circuit current,
damaging the USB port... this is a good idea to place a low ohm resistor to charge capacitor...
Why not just throw a diode in to prevent discharge?
bustatech (author)  progman323 years ago
Ya, notice about that issue, and I actually update a new circuit at step 7 and step 8 with the charging resistor included.
charger252 years ago
Very interesting item. Nice led
My version, based on your Instructable. The two 1-F, 5-V super caps are connected in series with a 10-Ohm resistor (behind the round PCB). The 330-Ohm, current-limiting resistor is attached directly to one of the LED legs. All this fits in a small Altoids tin.
Mvtnns2 years ago
2 Farads?!?!?

Isn't that more than twice than earth's capacitance?!
SinAmos2 years ago
TechKid672 years ago
So in theory, could you attach a few of this set-ups to a 5v solar panel but with a few adjustments: Switches on the lights so they just charge and aren't lighting when not in use. Also, can the supercaps. be over charged?
p.s. Im looking toward ideas for a handy emergency light source
keithyboyx3 years ago
hi, relative newbie here, but how would you suggest wiring 5x capacitors to the circuit. forgive me i am new. thanks
bustatech (author)  keithyboyx3 years ago
To use 5 capacitors, simply parallel them.
Nice. I want to make one with a pair of these.
account3r23 years ago
What voltage does the LED need to be?
A white LED uses 3.0 VDC.
bustatech (author)  account3r23 years ago
The forward voltage for White LED is around 3V.
This seems like it would be a pretty neat technology to use in an IR pen input. Do you know if Supercaps are sensitive to being charged for too long? Or do they just reach their maximum and let any excess pass through?
Caboose983 years ago
awesome! how much was teh capacitor? i want to make this in a little flash drive case.
robot13983 years ago
whats the need of knowing the polatiry
if you dont connect it right the capacitor will short circuit make the capacitor hot and maybe make it explode.
loppy963 years ago
will you get shocked to sh%^ if you touch the capacitor leads or?
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