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Stacking Capacitors

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Nostrafus

New Member
Aiight, here's one for you, I wanted to know if there was any way to stack capacitors to where you have capacitors going up in capacitance all the way up to a large capacitor (starting from about 1uF to 500uF) so that instead of them all discharging at once, when the top reaches full capacitance and discharges, the others are already at full power so there's not as long of a waiting period before it discharges again.

Any Ideas, would putting capacitors in series do this, or would they all just discharge at once ?
 

Ravi

Member
I think putting caps.in series would do this. Because the reciprocal of the effective capacitance is equal to the sum of the reciprocals of the individual capacitance.However,in high volatge applications it is necessary to equalise the d.c polarising potential developed across the each cap.by putting equalsing resistors across.
 

bogdanfirst

New Member
so you want to have 2 caps, so that alternatively when one charges, another discharges and viceversa, so that you can have all the time a full cap with available energy?
seems like you want to build a flash that stays always on.
my idea is to use a 555 with 505 ratio and use 2 transistors for each cap, one to connect the cap to the source and another to connet the cap to the load. the 555 drives them alternatively. and on the other cap, the transistors are driven opposite.
think this is a good idea?
 

Nostrafus

New Member
Not quite bogdanfirst, i guess I didn't explain properly.

Okay, say I wanted to stage up a large discharge, like 500uF, but didn't want a really long waiting period.

What I wanted to know is if there was any way to arrange the capacitors so that say, they're in an order like 1uF, 2uF, 4uF, 8uF, etc. all the way to 500+ so that the initial charge time may be long, like 10-20 seconds, but when the highest discharges, the others are already at full capacity, so it would only be a 3-5 second waiting period.
 

lavenatti

Member
Like this...
 

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lavenatti

Member
The caps would all charge at the same time. With the diodes in place, discharging one of them (I put transistors here for this) would not affect the charge on the others. It would start charging immediately after the transistor stops conducting.
If you put resistors in series with the diodes you would reduce the current draw on the power supply - this may or may not be necessary depending on the current rating of both the power supply and the diodes.
 

mstechca

New Member
So you say you want to discharge a large capacitor without alot of waiting time?

The easiest way is to take the most dangerous route. Connect both leads of the same capacitor together. You will see a spark. After the spark has gone off, the capacitor is discharged. This process takes about 1 second. The longer you normally wait for the capacitor, the bigger the spark. The sparks are more noticable on 1000uF+ capacitors.
 

bogdanfirst

New Member
Mstechca,
i think that if are wrong.....
the capacitor has a limited charge inside, so it will fully charge, and then you can wait as much as you want, but still it will have no effect.

ok, now i was curious about somthing Nostrafus......
whu can't you use 2 caps with a larger value ? like 2 1000uF caps? have them discharged in turns?
or maybe 3.....?
 

Nostrafus

New Member
Would it be possible to do that using one switch/pushbutton rather than more than one in the above schematic, sort of a protection from having it discharge before it reaches full capacity.
 

Nostrafus

New Member
Okay, just an FYI, this idea is for a "Stun Sword" similar to a stungun, except with 3 foot electrodes made out of steel pipes, that's why I wanted a large capacitance with a low wait time, and since I wanted it to be able to fit into one hand and used in a similar fashion as a sword, I wanted it to be compact using only capacitors instead of a larger transformer.
 
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