Re: 555 / timer / driver
Sent: Monday, November 24, 1997 12:06 AM
Subject: Re: 555 / timer / driver
Just a quick note here ---
I got the schematic ---
Are you using a standard 12 volt coil or a high energy coil ?
A standard coil requires a condenser across the points (.22ufd or
---- its mission is two fold --- it keeps the points from being destroyed
-- but more importantly ,it and the primary of the coil form
a series resonant circuit ---the frequency of which
is fairly standard but may vary a bit from manufacturer
to manufacturer ---- so the coil and condenser should be matched.
Also some coils require a ballast resistor ----
The schematic has the polarity of the coil reversed ---
--- the (+) goes to the ignition & ( -) to the points (gnd)
unless it has to do with Lord Lucas ( British) in which case
it is positive earth--in either case the polarity of the high
voltage is negative in automotive applications -else the spark plugs
don't last too long .
The inductive "kick " from the reversed polarity on the
coil is what is killing you I think ----
hope this helps ,
in a message dated 97-11-23 22:02:13 EST, you write:
<< Subj: Re: 555 / timer / driver
Date: 97-11-23 22:02:13 EST
From: ch038map-at-mode.lanl.k12.nm.us (MATTHEW A PRICE)
The schematic for the coil driver I used is at
this is a really good page for HV stuff. good luck, and tell me the
results, i'm still haveing problems.
On Sun, 23 Nov 1997 DamDeName-at-aol-dot-com wrote:
> Hi Matthew,
> Iv'e seen some of this thread but have lost some of my
> mail ----- could you send me a schematic ?? I'm
> currently working on a 555 ckt. to drive a pair
> of high energy ignition coils --- maybe i could help ?