Re: Electronic Ignition drivers for TCs/ which type is best?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Emil J. Schauer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <eschauer-at-adelphia-dot-net>

Are you talking about a TC driven by an automotive ignition coil? If so,
what are the detail.

Emil Schauer, in Cleveland Ohio

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, December 24, 2002 11:16 AM
Subject: Re: Electronic Ignition drivers for TCs/ which type is best?


 > Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
 >
 > Tesla list wrote:
 >  >
 >  > Original poster: "Jolyon Vater Cox by way of Terry Fritz
 > <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >  >
 >  > When an ignition coil used to provide HV for a tesla coil it is good
idea
 >  > to use electronic switch to turn the primary current on and off.
 >  >
 >  > One way use a 555 astable to gate the input of an electronic ignition
 > driver.
 >
 > A known very efficient method to destroy 555s, power transistors, etc...
 > Works, but if you look at the waveforms, there is a great possibility
 > that the 555 is being retriggered by the radiated pulses of the ignition
 > coil, and that its timing RC circuit is not doing anything...
 > (Ok, I know that with proper construction the thing works.)
 >
 >  > Electronic ignition drivers come in two main types (i) inductive
ignition
 >  > and (ii) capacitive-discharge ignition or CDI.
 >  >
 >  > Which of the two is best for driving a coil that is powering a TC?
 >
 > Difficult to tell, since a diode in the circuit turns everything
 > into a nonlinear circuit. Probably indifferent.
 >
 >  > My guess is that inductive ignition is better as it gives a longer
duration
 >  > output spike which might be better for charging capacitors
 >
 > No difference. The output, even without any load, is not a spike, but
 > a smooth almost sinusoidal pulse containing two widely separated
 > frequencies. Much as in a Tesla coil with (very) high coupling
 > coefficient. With a diode and a capacitor to charge, this waveform
 > will appears, approximately, only when the output capacitor is
 > fully charged, after several cycles.
 >
 >  > maybe "inductive" nature of charging circuit better balances the
 >  > capacitance of the tank cap but I am not sure here. I do know that CDI
 >  > gives very short output spikes
 >  > -possibly not so good for charging capacitors- am I correct or
incorrect on
 >  > this matter as I am currently using 555-gated Velleman K2543 inductive
 > driver.
 >
 > Look at the output, without sparking, using an antenna and an
 > oscilloscope, and you will see a smooth pulse with a high-frequency
 > ringing added to it. The frequencies are in the kHz range, usually.
 >
 > Antonio Carlos M. de Queiroz
 >
 >