Instructables

Portable capacitor charger with detachable capacitor!

This is my camera cap charger circuit (the wire goes through the board for wire stress relief) connected to a AA battery (the blue tape is for wire stress relief).

The unique (probably) part of this project is that I used two small magnets from a computer hard drive to make the capacitor detachable.

Remember to comment and rate, Thanks!

BTW Sorry I couldn't get more pics, I was fighting with the camera, it eats those puny AA batteries in minutes
can you 'trickle' charge a capacitor?

I understand that a capacitor must be charge by the same voltage that the capacitor can hold before the plates reject incoming. I.e. - a 9v battery can charge a capacitor to 9volts. No more no less.

There is though, no mention of amperage. Can you trickle charge a capacitor at 9volts, but 0.001amps, and over time, achieve a fully charged capacitor capable of discharging 9v worth of energy? Or is there a pre-determined 'amp' rating that capacitors must be charged at?

Thanks.
thermoelectric (author)  whiskeysausage1 year ago
Yes, you can trickle charge a capacitor. Just throw a resistor inline with it to limit current. When it is fully discharged it will look like a short circuit, so it'll try to draw the most current there. With a resistor it'll be pretty constant.

Also, if you charge at too low of a current (very very small) you may experience the leakage overcoming the charge rate, so you may have to feed it more to get to higher voltages.

Cheers.
what if I trickle charged a 5v rechargable battery, and then released the battery into the resistor? would this work?
thermoelectric (author)  whiskeysausage1 year ago
That should work.
And would amps be more important, or volts? If stair-step trickle charging? Should I use a something like a 3 volt 45mah battery, or a 3v 7mah battery?
thermoelectric (author)  whiskeysausage1 year ago
Capacitors charge in a very exponential (I think that's the word) manner, see this graph. It really depends on what you want to get out of it, a smaller battery (capacity, mAh) will reduce the number of times you can charge the capacitor, not necessarily the charge rate.

Once the capacitor is charged, it is charged. Short it out or put a load on it, either will release the charge.
the big question of the day morning then, is 'how' do I get the battery to do release, upon reaching 5v threshold to the capacitor, so that the capacitor has 400+mf?

Or, if the battery is being trickle charged, will the battery's charge feed into the capacitor, and then once voltage is equalized, will the battery then continue to charge - then once the battery is charged higher than the capacitor - the cycle begins anew, until both the capacitor and the battery have equally high charge?

In essence, if they were hooked up in parallel, would they just 'stair-step' charge themselves to a maximum charge?
mattccc5 years ago
i actidently touched the leads of a camera capacitor it scared the S#!T!!!!!! out of me and it left a burn mark on my finger
if you conect the leads or both sides of the flashbulb to wires and re case it you can make a really good shocker. but for more fun with capacitors check out disposible camera coilgun it is awsome.
thermoelectric (author) 5 years ago
283 views and no comments? C'mon
Same thing happened to me except ~less~ more views before I had a comment.
~~less.~~
thermoelectric (author)  bylerfamily5 years ago
Ah.
mattccc5 years ago
but nice idea