555 timer driver for ignition coil

["wsc1914" <wsc1914-at-hotmail-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I have finally suceeded in getting the driver circuit
 http://www.geocities-dot-com/CapeCanaveral/Lab/5322/coildrv.htm ) for an
ignition coil to work. However, when I disconnet it and connect it the 555
timer chip sometimes burns out and fails to work any more. What should I do?

I heard somewhere that I need a filter, but what on earth is that, and how
do I connect it?

Any help would be gratefully received at wsc1914-at-hotmail-dot-com !

Many thanks!

Oliver.