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Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
Ash Small wrote ... ...I've also been thinking, as E=1/2CV^2, does it make more sense to connect capacitors in series, rather than in parallel? (more voltage, but less charge, but energy is a factor of V^2)
Ash, you ought to know better. The stored energy in a capacitor bank is not changed by converting from parallel to series connections, and neither is the maximum power output. The capacitance, resistance, and inductance between the bank terminals change by a factor of N^2. One configuration or the other might be a much better match for a particular ETG bridge or coilgun coil.
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
klugesmith wrote ...
Ash Small wrote ... ...I've also been thinking, as E=1/2CV^2, does it make more sense to connect capacitors in series, rather than in parallel? (more voltage, but less charge, but energy is a factor of V^2)
Ash, you ought to know better. The stored energy in a capacitor bank is not changed by converting from parallel to series connections, and neither is the maximum power output. The capacitance, resistance, and inductance between the bank terminals change by a factor of N^2. One configuration or the other might be a much better match for a particular ETG bridge or coilgun coil.
It's hard to argue against experimental results.
Well, I know that 1/Ct=1/C1+1/C2+1/C3.....+1/Cn, and the equation I quoted above contains a V^2 function, and I did find it puzzling that energy is a function of V^2. I also assume that the 'C' in the equation I quoted stands for charge (C=Coulombs). I'll have to look into this in more detail.
Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
We need seven posts so clarify that you cant charge capacitors in parallel, then wire them in series and end up with more energy than before -.- great job. Does someone to accompany me? I take a walk - cant stop crying about this -.-
Yeah, those guys need to pay a visit to school one day...
Energy of capacitor is E=C*U*U/2, where C is a capacitance in Farads. The charge capacitor holds is expressed in Coloumbs: q=C*U When two caps are connected in series, the charge each one holds does not change - the effective capacitance becomes two times smaller. So as chain holds doubled voltage, the capacitance is halved. Addition for curious ones: q=C*U=I*t, where I is a current and t is a time. I found that derivative very useful: dU = I*dt / C It shows for how much volts (dU) cap's voltage will change for some period of time (dt) if cap is being charged with a constant current (I).
Registered Member #3302
Joined: Sun Oct 10 2010, 02:21PM
Location: Finland
Posts: 42
I will build a new chamber with a similar design than the old one but I will use iron rod instead of nylon, 5mm wall thickness should hold inside anything I put in there. I will post pictures and a diagram of its structure when its ready and a video of it shooting a steel projectile through some stuff :)
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