222 lines
11 KiB
Plaintext
222 lines
11 KiB
Plaintext
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| File Name : LOW$$CAP.ASC | Online Date : 11/25/95 |
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| Contributed by : Jon Snell | Dir Category : ENERGY |
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| From : KeelyNet BBS | DataLine : (214) 324-3501 |
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| KeelyNet * PO BOX 870716 * Mesquite, Texas * USA * 75187 |
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| A FREE Alternative Sciences BBS sponsored by Vanguard Sciences |
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| InterNet email keelynet@ix.netcom.com (Jerry Decker) |
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| Files also available at Bill Beaty's http://www.eskimo.com/~billb |
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This design is a variation on the more powerful capacitor designs introduced
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by Bert Pool in CAPACITR.ASC. I can't really take any credit beyond the few
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modifications that I'm offering in this text. Sorry Bert! Your design was
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inexpensive but not DIRT CHEAP. I had to test the limits of my household
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materials and stay within my research budget limits.
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; How to build a CHEAP CHEAP CHEAP ;
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; 5 Kv Capacitor ;
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; ;
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; by Jon Snell ;
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; ;
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; 9/28/95 ;
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I've been working on various F/E experiments using pulsed HV in the low
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kilovolt range and I didn't feel like paying large sums of cash for high
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voltage capacitors. To build a bank of electrolytic capacitors for my purposes
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begins at around $180. For less than $30 I can build several oil filled caps
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with many times the storage capacity per $ of those nasty commercial
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electrolytics. Sure, electrolytics take up less space, but who cares about
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space when $$$ are at stake?! (especially on my budget)
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This is a text on constructing an oil filled capacitor for holding 5-8 kv. It
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seems to be quickly usable (within 1 week) without HV breakdown. I've been
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beating on a couple with about 7.5 kv for a couple of weeks with no problems.
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I used the second one about 20 minutes after filling it with oil and it
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performs just as well as #1 does (go figure).
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You need 4 mil or 6 mil poly sheeting from the hardware store and a good long
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roll of aluminum foil from the wife's kitchen cabinet. These plans are not
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exact and may be modified to suit whatever needs you may have. Just remember,
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more surface area = louder BANG!
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Formula for figuring Capacitance in pF:
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C= 0.2235 * (KA/d) * (N-1)
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C = Capacitance in pF
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K = Dielectric constant of insulator
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A = Area of one plate in square inches
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d = distance between plates in inches
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N = number of plates
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Remember: mfd or uF = .000001 Farad
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mmfd or pF = .000000000001 Farad
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Parts list:
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- A length of 2" O.D. (or 3", 4", 5", etc...) PVC pipe.
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- A length of 1/2" pvc.
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- 2 end caps for the PVC.
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- PVC cement
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- Clear silicone RTV
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- #22 HV insulated solid aluminum wire (or Delco 440 ignition wire)
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- Two 1/8" bolts 1 inch long with nuts
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- A roll of 4 mil or 6 mil plastic sheeting from the hardware
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store. Polyeurythane is the best for the $.
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- A roll of household aluminum foil.
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- 1/4 inch thick plexiglass
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- plastic wire ties
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- Mineral oil (from pharmacy)
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This is fairly simple. Cut your pipe about 6 inches longer than your roll of
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foil. Clean one end of the pipe and the inside of the endcap with alcohol.
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Liberally apply the cement to the pipe end and twist the cap in to place to
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securely seal the end. This is the bottom of the capacitor.
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Cut two 1 3/4 inch long by 1 inch wide rectangles from the plexiglass. Cut a
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center slot halfway through the width of each so that they'll fit together
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like an X. Drop this assembly into the bottom of the pipe. Your capacitor guts
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will sit on top of this to keep them out of moisture that may collect on the
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bottom.
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If your using 2" pvc then the lengths I'll suggest will work nicely. Scale
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them up for larger pipes. Cut two 13 foot lengths of poly sheeting that are 4
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inches wider than the width of the aluminum foil.
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Cut a length of 1/2" pvc that is 1 inch longer than the width of the poly
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strips. Cut a 1/4" notch in one end. Strip several inches of the aluminum wire
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and feed the stripped end down through the tube and out the notched end. Bend
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the wire at the base of the stripped end and hook it in the notch so that the
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bare wire rests against the outside of the tube and the insulated part is in
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the center.
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pvc ______________________________________________
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wire > ========================================================\
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___________________________________________\___
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=============================== /
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bare wire
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Lay out one 13 foot poly strip and tape down both ends to the floor with just
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two tiny pieces of tape (this is tempory to stabalize construction). Unroll
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your foil down the full length of poly. Leave even spacing on both sides and
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overlap the poly on one end by 1". Tack this in place at each end with tape
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(again, only a little because this is temporary).
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Now place the second length of poly sheeting directly over the first (tape on
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ends to hold in place). Unroll another layer of foil, but overlap edge by 1"
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on opposite end from the first layer. Wrap the overlap from the top foil layer
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around the 1/2 " pvc and wire assembly so that the bare wire contacts the
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foil. Remove tack tape on this end and begin rolling the aluminum/poly
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sandwich up on the pvc/wire assembly. Keep everything straight when rolling.
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When you reach the far end you should have a little foil hanging out from
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bottom layer. Strip the end of another piece of wire and roll the foil
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overhang onto the bare area. Now use the wire ties and secure the whole roll
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so that is doesn't unroll. This will also hold the wire onto the side. Don't
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cinch the ties any tighter than it takes to hold everything in place or you
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may damage the poly with the wire.
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Cut a square of plexiglass that overhangs the end of the 2" pipe on all on all
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sides. Drill holes for 2 vacuum fittings and 2 1/8" bolts.
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-------------------------------
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|\ / |
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| \ bolt / |
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| \ x / |
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| \ / |
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| \ / |
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| vac \ / vac |
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| x \ / x |
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| / \ |
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| / \ |
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| / \ |
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| / x \ |
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| / bolt \ |
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| / \ |
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------------------------------
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After drilling the holes then lightly score the surface of the plexi from
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corner to corner in both directions (like the letter x). This will allow the
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plexi to crack if there's ever a sudden pressure build-up due to capacitor
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failure.
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Place roll into the 2" pvc assembly and place plexi cap on pipe. Measure and
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cut wires so that they will reach the bolts. Double check your measurements
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before cutting wires. You don't want any mechanical stress on anything inside
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the capacitor. Feed the bolts through so that the threaded ends stick out the
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top and attach the wires underneath. Seal the bolts in from top and bottom
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with RTV. Seal vacuum fittings in place with RTV.
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Coat the top edge of the pvc pipe with RTV and seal down the plexi endcap.
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Close one vacuum fitting and apply a light vacuum to the other. Listen for
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hissing and seal any leaks. If oil escapes you'll have a real nice mess. Let
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the RTV cure for 24 hours.
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Now run some hose from the other vacuum fitting into the bottle of oil and
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apply vacuum. The oil will be sucked into the capacitor. Stop filling when the
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oil is about 1/4" over the edge of the poly. Seal off the second vacuum
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fitting and continue applying vacuum to the canister. Don't let the oil foam
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up into the vacuum hose to the pump. This will destroy your pump. Run the pump
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for about 1/2 hour to get most of the air out.
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Let the capacitor stand on the shelf for about 5 days before using it.
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This gives it time to release any remaining air. If you promise not to use
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more than 5kv then you could probably use it immediately. My first tests were
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using a DRY rolled capacitor just to see what it would take before it fried.
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Just use some of the material that's left over and make a small test
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capacitor. Drop it in a plastic tube but leave it dry.
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Using a 700-15000 volt variable D.C.inverter, steadily crank up the volts
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until you reach the breakdown point. This will be your PEAK voltage rating. A
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safe working voltage will be about 2/3 of your peak.
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NEAT TESTS: Place a 12" by 12" poly square on tile floor.
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Place a 10" by 10" foil square on the poly, attach HV lead.
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One more layer of poly, and one more layer of foil. Attach
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other HV lead to top foil layer. Now place one more sheet
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of poly over it all. Apply HV DC and listen to the crackling
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as the plates charge. Discharge and charge several times.
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Now turn off the HV DC source and discharge plates fully.
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Don't touch until foil plates have been shorted together!!
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Pick the layers apart and notice how the charging makes the
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poly and aluminum pull together in a fairly tight bond, forcing
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the air from between the layers.
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If you used 4 mil poly then don't use much more than 5 kv DC with this and you
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shouldn't have any problems. If you want more voltage then put several of
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these babies in series (i.e., 3 caps in series = 15 kv).
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Paralleling them gives you the same voltage but greater capacity.
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Series reduces capacitance but increases total voltage rating.
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Ct = total capacitance
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C1, C2, C3...etc. = capacitance of individual capacitors in circuit
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Capacitors in parallel : C1 + C2 + C3...etc = Ct
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1
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Capacitors in series : Ct = --------------------
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1/C1 + 1/C2 + 1/C3 ... etc.
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Capacitors should stand vertically in a metal pan. This catches oil in the
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event of a leak. It also acts as fire-proofing if a capacitor ignites
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(unlikely but still possible).
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NO WARRANTIES, GUARANTEES, OR ANYTHING ELSE EXPRESSED OR IMPLIED.
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YOU BUILD THIS AT YOUR OWN RISK. HIGH CURRENT LEVELS IN THE LETHAL
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RANGE ARE POSSIBLE. DISCHARGES FROM CAPACITOR CAN CAUSE SKIN TO
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FRY OR EXPLODE (ouch). IT IS IMPOLITE TO DETONATE BUGS OR OTHER
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TINY CREATURES WITH HIGH VOLTAGE. KEEP PETS AWAY!!!
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See also: FLYBACK.ZIP - How to build a CHEAP CHEAP CHEAP solid state
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5 kv - 15 kv inverter. With gif schematics.
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------------------------------------------------------------------------------
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