Re: Car Ignition Coil (fwd)

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Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 18 May 2007 10:42:36 -0700
From: Ed Phillips <evp@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Car Ignition Coil (fwd)

Tesla list wrote:

>Original poster: List moderator <mod1@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Thu, 17 May 2007 19:10:38 -0600
>From: Michael Robinson <muze801@xxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Car Ignition Coil
>
>I've been trying to get a car ignition coil to function as a power
>supply and can get a single thin spark about an inch long every time i
>complete the circuit but it won't spark again after that unless I
>repeat.
>
>I'm running with a 10uF cap that I pulled from an air conditioner with
>mains power (120v)  and I tried some much lower capacitance caps with
>the same result.
>
>Any ideas?
>Sincerely,
>Michael Robinson
>
    Hard to give any useful reply without more information on the 
circuit you're using.  Sounds as if you're connecting it to a 
low-voltage source (battery?) and talking about the coil output; if so 
you should expect a single spark each time you BREAK the circuit.  That 
would be normal and a 1" spark is pretty good if you're talking about 
the ignition coil output.  Not clear where the 10 ufd capacitor is 
connected..................  If you want to use a low-voltage source you 
need some form of interruptor circuit to make and break the circuit and 
you'll find plenty of those on the web and in the archives.  Some of the 
others here have suggested using the "light-dimmer" approach to powering 
the coil from mains power and that works fine although 10 ufd is a 
pretty large capacitor (try 3 ufd or so and make sure the voltage rating 
is at least 600 volts) and running with it would probably end up with a 
shorted dimmer, a fried coil, and smoke. 

    If you're talking about some kind of TC then you need to give us a 
lot more circuit details to get any worthwhile advice at all.  The 
primary capacitor for that coil would be more in the vicinity of 0.01 
ufd and of an entirely different construction to keep the RF losses down.

Ed