Re: Staccato Problem Solved - I Think

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Mddeming@xxxxxxx 

In a message dated 9/7/05 12:41:49 A.M. Eastern Daylight Time, 
tesla@xxxxxxxxxx writes:
Original poster: "Chris Fanjoy" <zappyman@xxxxxxxxxxx>

   I was getting tired of trying to correct the problem I mentioned
in a previous post. I couldn't seem to keep RF noise from reaching
the gate of the SCR, causing the coil to operate in CW rather than
pulsed. Then I got the bright idea to use a relay. Instead of using
the staccato pulse to drive an SCR, I used it to feed the base of a
transistor, which then applies the required voltage to a small relay.
It seems to work great in initial testing; the coil can now run at
full voltage without any apparent problems. But it will be some time
before I see how the relay holds up - some sparking occurs on the
contacts, so I'm guessing they won't last forever. The other downside
is that the pulse width must be quite wide to trigger the relay. And
of course the relay makes a bit of noise, but it's still nothing
compared to a conventional spark gap!
   Anyway, I think this project is finally back on track. I'm
surprised nobody has suggested the use of a relay before....



Hi Chris,

It probably hasn't been mentioned because at any decent PPS frequency 
the contacts do tend to spot weld or burn off in fairly short order.

Matt D.