Re: My findings on 555 Ign. Coil spark maker thingys

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Or use a better power transistor with more gain than the 3055 (which has a
beta of 10-15... not too wonderful, because you probably need 3-4 A to the
coil, which means it needs 300-400 mA of base drive.)  Given that this is a
switching kind of circuit, one of the TIPxxx  darlingtons might work better.
The power dissipated in the transistor is fairly low.  You'll also avoid
killing the 3055, which is only rated for 60V Vce

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, December 01, 2001 10:02 AM
Subject: RE: My findings on 555 Ign. Coil spark maker thingys


> Original poster: "Michael J Strube by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <mjstrube-at-artsci.wustl.edu>
>
> Bob,
>
> I've played around with that design too and have found that putting a
> transistor (a 2N2222 in my case) between the 555 and the 2N3055 helps a
> lot. That way you can keep the 555 output current at a more reasonable
> level (by using the 2N2222 to step up to the 2N3055).
>
> Mike
>
> -----Original Message-----
> From: Tesla list [SMTP:tesla-at-pupman-dot-com]
> Sent: Friday, November 30, 2001 9:17 PM
> To: tesla-at-pupman-dot-com
> Subject: My findings on 555 Ign. Coil spark maker thingys
>
> Original poster: "Bob Bozarth by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <jbdetails-at-prodigy-dot-net>
>
>     Aside from a few major components, all of my first coils effort has
been
> spent on the Ignition coil driver from
> <http://www.geocities-dot-com/CapeCanaveral/Lab/5322/coildrv.htm Except I>
changed the single to a
> dual coil. I did this by connecting the - to + and the + to - on the two
coils.
> Then the one each of the output wires from the timer went to one of
the -/+
> crossover wires on the coil. It worked really good, but I had some extra
> transistors and wanted to experiment a little. I found a MJE3055T, which
is the
> same as a 2N3055 but in the smaller TO220 package.Worked twice as good,
yet
> barely got warm where the 2N3055 wood got hot enough to sizzle a moist
> fingertip. I just wanted to share this tidbit. For all I know it's common
> knowledge to most but I feel good when I discover things like this. If
only I
> could figure out how to not toast my 555 timers, there're so sensitive. I
know
> they are cheap but 2 to 3 a day? ( I experiment allot!)
>
>     Bob Bozarth
>     Experimenter
>
>
>
>