#garfield Logs

Oct 14 2014

01:43 rue_bed-aok so you need to add 5 coulombs/sec to keep the voltage the same
01:44 rue_bed-aok so, for a given voltage, what capacitance change will require 5 coulombs/sec to keep the volatege the same
01:44 rue_bed-aok I might be too asleep for this
01:45 rue_bed-aok Q=IT
01:45 rue_bed-aok I is the same, 5A
01:45 rue_bed-aok t is 1 sec
01:45 rue_bed-aok so Q is 5
01:45 rue_bed-aok right, that was a short little circle
01:46 rue_bed-aok V=
01:46 rue_bed-aok hmmm
01:48 rue_bed-aok V/T = I/C
01:49 rue_bed-aok thats not going to help
01:49 rue_bed-aok V is steady
01:50 rue_bed-aok hmm
01:50 rue_bed-aok C=Q/V
01:51 rue_bed-aok if Q = 5
01:51 rue_bed-aok and v is, say 40
01:51 rue_bed-aok something isn't right
01:52 rue_bed-aok Q=IT
01:52 rue_bed-aok so, 5A, 1 second, Q is 5 coulombs
01:53 rue_bed-aok I think the answer is 1250mF/sec
01:53 rue_bed-aok er no
01:54 rue_bed-aok 125mF/sec
01:54 rue_bed-aok if its 400V
01:54 rue_bed-aok then its 12mF/sec
01:55 rue_bed-aok 12500uF/sec
01:56 rue_bed-aok i = C(dv/dt)
01:56 rue_bed-aok therefore C = I(dt/dv)
01:56 rue_bed-aok dv = 0
01:56 rue_bed-aok so that wont help
02:06 rue_bed-aok http://www.ebay.com/itm/100pcs-Glass-Micro-Cover-Slips-Microscope-Slide-Covers-/321444026996?pt=LH_DefaultDomain_0&hash=item4ad78e9a74
02:09 rue_bed-aok http://www.ebay.com/itm/0-2ML-Silver-Conductive-Glue-Wire-Electrically-Glue-Paste-Adhesive-Paint-Repair-/390949794271?pt=LH_DefaultDomain_0&hash=item5b066c71df
02:10 rue_bed-aok http://www.ebay.com/itm/0-3ML-Silver-Conductive-Glue-Wire-Electrically-Glue-Paste-Adhesive-Paint-Repair-/390949795351?pt=LH_DefaultDomain_0&hash=item5b066c7617
10:21 TELunus Is mist actually real, or is that some spam bot?
19:51 rue_house notice bot
19:51 rue_house TELunus, any luck with the calculations?
19:52 rue_house (TELunus, at what rate would the capacitance rating of a capacitor need to change at to draw 5A continiously from a 400V dc supply?)
19:53 TELunus Uh, I'll let you know in a bit, let me grab some paper.
19:55 rue_house its fun, a bit of an inside out problem
20:03 TELunus If I = C*dV/dt
20:03 TELunus and V is constant
20:04 TELunus then I = 0
20:04 rue_house but your taking the same number of electrons and spreading them over mroe plate area
20:04 TELunus So I'm assuming you're going off I = d(C*V)/dt
20:04 rue_house couldn't
20:04 rue_house same problem you just had
20:05 rue_house when you change the seperation of the plates of a capacitor the votlage ont eh plates changes
20:05 TELunus Ah
20:10 rue_house so to mainteain the votlage, a current is needed
20:10 TELunus So, looking at the real formula: C = q/V
20:10 TELunus Let's move the V to the other side.
20:11 TELunus CV=q
20:11 TELunus taking the derivative with time: d(C*V)/dt = I
20:11 rue_house ah!
20:11 TELunus V is constant, I is 400
20:11 rue_house no
20:11 rue_house I is 5
20:11 rue_house V is 400
20:12 TELunus Ok, whatever.
20:12 rue_house :) minor details
20:12 TELunus So I = V*dC/dt
20:12 rue_house 5, 400, nasa dosn't worry about it, why should I?
20:12 TELunus dC/dt = I/V
20:13 rue_house dt = 1
20:13 rue_house so you get the same answer I did, 12.5mF
20:13 rue_house and you went a completely different route
20:13 TELunus dC/dt = 5A/V
20:13 rue_house coool
20:13 TELunus Sorry: 5A/400V
20:14 rue_house so, 12.5mF/sec
20:14 TELunus Cool.
20:16 rue_house :) now, design a capacitor that increases at 12.5mF/sec without ever increasing, hint: use a circle
20:17 rue_house +208.3uF/(1/60 sec)
20:19 rue_house ah!
20:19 Tom_itx supercaps?
20:19 rue_house changing the dielectric also causes the votlage to change
22:48 rue_house during 1 cycle, a 240VAC 2kw load consumes the energy of a 207.5uF cap charged to 400V
22:49 rue_house the peak votlage of a 240VAC sine wave is 336V
22:54 rue_house http://upload.wikimedia.org/wikipedia/commons/3/35/Wimshurst.jpg
22:55 Tom_itx rue_bed-aok where did you get your web host?
22:55 rue_house irc emmeber
22:55 rue_house member
22:55 Tom_itx link?
22:55 rue_house its hackman127
22:55 Tom_itx oh
22:55 Tom_itx i forgot
22:55 rue_house iirc
22:55 Tom_itx does he sell space?
22:55 rue_house long ago
22:56 rue_house let me find his email...
22:56 rue_house there are like 30 sites on his server
22:58 rue_house you going from home now?
23:00 Tom_itx no some guy is looking
23:00 rue_house luke @ cowgar . com
23:00 rue_house ah
23:00 rue_house I dont know if I'd try that then
23:02 Tom_itx k
23:02 Tom_itx what's a good price for domain and space?
23:03 rue_house I'd expect about 1G free-$20/mo
23:04 rue_house how about rackforce