[Prev][Next][Index][Thread]

Re: KV's and multimeters


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Sunday, November 23, 1997 2:54 PM
To: 	Tesla List
Subject: 	Re: KV's and multimeters

Hi Matthew,

> From:   MATTHEW A PRICE[SMTP:ch038map-at-mode.lanl.k12.nm.us]
> Sent:   Friday, November 21, 1997 1:45 PM
> To:     Tesla List
> Subject:    RE: KV's and multimeters
> 
> 
> >
> > >From:    MATTHEW A PRICE[SMTP:ch038map-at-mode.lanl.k12.nm.us]
> > >Sent:    Wednesday, November 19, 1997 10:47 AM
> > >To:  Tesla List
> > >Subject:     KV's and multimeters
> > >
> > > 
> > >Last night I finished the driver for the ignition coil useing a 555 timer.
> > >I was surprised when I hooked the thing up and it actually worked!
> ........voltage its putting out? My multimeter is a cheapie that only
> goes up to
> > >1000 V. Also why does it spark to everything..even when its not grounded?
> > >
> > >Matthew
> > >
> > >If you want to make better sparks, put in a variable resistor in the
> > 555 circuit. Tune it until you get the longest spark. The best ignition
> > coils are the red or blue ones. These are specially for use w/ transistors.
> > Also, TV transistors arent the best. IGBTs are the best, but simply a 3055
> > is ok. My ignition coil throws 3/4 inch sparks easily. Or, if you want to
> > make the longest and fattest sparks, use a thyristor in series with a 1uf
> > cap and the primary. Feed this arrangement with 250 VDC. The cap charges up
> > and discharges throught the primary. I used 350 VDC and a 4,7uf cap, that
> > made 2 1/4 inch sparks!
> > Atle Jorstad
> 
> Help!!!! The driver that I was talking about is now giving me seriuos
> problems. I replaced the TV transistor with a 3055 and the voltage was, as
> you said, increased, but the thing quit working. After trying a few things
> I decided to try a new 555, and it worked again, but quit again. I decided
> not to fry anymore 555 (thats what I was doing, and the things don't grow
> on trees!) so I wanted to ask you guys what I am doing wrong. Part of the
> problem may be that I need a higher voltage rated wire, but I don't know.
> The second time it only ran for a few seconds, and I didn't touch
> anything... Please tell me what I am doing wrong
> 
> Thanks
> Matthew

In all probability you are generating spikes that are exceeding the 
Vces of the 2N3055 by a subtantial amount. Check your data sheets.

Malcolm