Re: Plastic soda bottles for bypass caps? (fwd)

---------- Forwarded message ----------
Date: Thu, 18 Dec 97 00:56:29 -0500
From: Adam <absmith-at-tiac-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Plastic soda bottles for bypass caps? (fwd)

>> I had the same problem also. Here in good old OZ, things such as
>> doorknob caps are not only hard to get hold of but damn expensive! I
>> then decided that making bigger chokes and not using any bypass caps is
>> a much cheaper solution. I have been using 30 mH Pi wound chokes and
>> safety gaps only and have not lost a Neon sign transformer since.
>You really shouldn't be at a loss for a bypass capacitor, since they need 
>be only around .001 ufd and have a voltage rating exceeding you transformer
>they can be cheaply made out of polyethylene film and aluminum foil.

Good advice.  I looked at the doorknob cap prices, I considered using PET 
bottles, but ended up with enough 0.030" LDPE scrap left from my main cap 
project to build two nice 60mil 500pF bypass caps.  I didn't bother with 
oil for these guys, but I may pot them with vasoline or paraffin in a 
1-1/4" PVC tube when I get done polishing up the really important parts.

BTW, some people recommend lossy caps for bypass units, and others don't. 
 My personal feeling is that it doesn't make one bit of difference.  You 
are shunting unwanted RF to ground, trying to get rid of it as fast as 
possible, so who really cares if a few percent is lost to heating?  You 
certainly aren't going to have enough current for dielectric meltdown at 
60Hz with only 500pF, and when your coil is tuned you will have only VERY 
little intermittent RF current in these guys too, esp. if your chokes are 
doing their job. 


Adam Smith
Epoch, Inc. Digital Music Project

www.tiac-dot-net/users/absmith/                 MP3 Demo Tracks Now Available!