[TCML] Capacitor calculator?
mrapol at verizon.net
Thu Sep 17 08:58:17 MDT 2009
I spent 18 months experimenting with Leyden jars made of various metals,
plastics, and glass. My preferred model--so far, I am still
researching--uses a Crystal Light powdered lemonade canister. It's a
straight sided cylinder 67 mm tall (about 6 and 5/8ths inches). The
canisters are made of fairly thin polypropylene. An empty, sealed, inverted
aluminum soda can will not quite fit in the canister; you have to warm the
plastic with a hair dryer before you can push the can in. (You also have to
make a small hole in the bottom of the canister to let the air out. This
hole you later plug with silicone caulk). With the can fully in, there's
room for a layer of wax or paraffin on top to suppress corona. Aluminum HVAC
tape makes the outside coating. Early on I settled on this as the best
choice. Household foil is too fragile.
I tried all sorts of metallic items to serve as the interior surface of a
Leyden jar: BB shot, copper pan scrubber pads, ball bearings, lead musket
balls, aluminum gutter flashing, regular household foil, powdered metal
applied over a glue coating, etc. All of these worked, but some were better
than others. The best combination of light weight, sturdiness, and
capacitance came from using soda cans.
Best of all, it's cheap. My kids drink the lemonade, I drink the soda, and I
can build an excellent Leyden battery out of the leftovers!
----- Original Message -----
From: "Daniel Kline" <daniel_kline at med.unc.edu>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Thursday, September 17, 2009 8:59 AM
Subject: Re: [TCML] Capacitor calculator?
> Very nice! What do you use other than peroxide bottles?
> Dan K.
> PAUL THOMPSON wrote:
>> Hi Brian,
>> I use a Leyden jar battery with my coils. The way I do it, I make a
>> sample single jar and test its capacitance with a handheld meter. I make
>> few more and test them to make sure I'm getting consistent results. For
>> example, I make a dry jar using polypropylene canisters and aluminum soda
>> cans that always clocks in at 450 to 500 pF. By linking a bunch of these
>> in parallel I get the capacitance I want. See
>> I don't make salt water jars. Liquids are heavy and messy, and I worry
>> about glass breakage. I've never had one of my homemade Leyden jars
>> break, melt, or arc over. Based on spark length when charged with my
>> Wimshurst machine, I estimate the voltage rating of my jars at 100 KV.
>> Paul Thompson
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