John Curl's Blowtorch preamplifier part III

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*When jneutron, RNMarsh etc. start talking about their little toys, Milou and I put our tin foil hat.

The silence. Very few people have the pleasure of working on a large scale physics machine. If lucky once. I had many which I worked on and got really good at coordinating their construction and development from the electrical and electronic side. When a machine was nearing completion and operational, I would go find another to start from scratch on. I was never interested in a career maintaining and modifying, afterwards. I recall, back in the day, going to the next big machine and introduced myself to the secretary. She said, i know who you are, your reputation precedes you. Wow. I didnt know. I guess she had been alerted or warned :)

Now I am kicking back here in my Bangkok condo, sold the farm, cars, everything and got my Sara from university break with me this week <3

Life is good. Except the getting old part. Its been interesting and music/audio has always been a part of it.... makes for a good relaxing way to unwind and relax.


THx-RNMarsh
 
Happy retirement!

I've changed the belt on a Van de Graff generator - does that count? :)
Ah, but it is not the belt that is typically the problem.

VDG's work on triboelectric. The separation of two materials with different electronegativities.

A typical VDH will have felt rollers on the bottom, and plastic rollers on the top. A comb picks up the excess charge on the belt as it leaves the plastic rollers.

The problem is, the plastic rollers will become coated with rubber from the belt, so the machine stops working. I used a file to remove the outer coating on the plastic rollers to fix the one we were using here for a science show.

Trust me that fixes the problem really, really....really well. (did I mention "really"?)

Oh, BTW, I heard "through the grapevine" that after you've cleaned the rollers and put the machine back together to test it...always, always, put the grounding rod and sphere back into place. Otherwise, when you turn it on, the sparks will run 1.5 to 2 feet from the dome, and should you "ahem"....place it so that you can't even reach the plug to pull that out, can't get to the doorway...but can only cringe in the far corner of your very small office hoping those lightning bolts don't hit because you were idiotic enough to place the godforsaken thing directly in your avenue of egress...sigh.....

But that's what I've heard... not the I would make that silly mistake..no, not at all...:eek::eek::eek:
jn
 
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My physics teacher at school decided that std issue VDG were not powerful enough so made a bigger dome about the size of a crash helmet. That gave good spark.



I thought that was impressive till my daughter went to Daresbury for a year and told me about the biggy they used to have there.


Particle physics. Hitting small things with ever bigger rocks just in case something happends :)
 
This turn of the thread really brings back some memories - eons ago (when I was a grad student) - I was licensed to operate a Van Der Graaf accelerator at Lowell Tech (MA) - it was 3 stories tall and ran at a potential of 2MeV (maybe higher). The inside was filled with Sulfur Hexafloride (to avoid internal arcing) - the control electronics were 2MV above ground & controlled by strings & pulleys from selsyn motors at the bottom (which were connected to knobs on the control panel).

All this was to simulate radiation damage in metals (I was studying nuclear materials) - after blasting the samples, I could put them into my pocket (if neutrons were used - not a great idea).

Not sure I could design one (as JN and RM have done) - but operating it was lots of fun.

Rich
 
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At the shop for Halloween we used to leave a dummy head sticking out of the press brake.

Now you guys have clued me in to something better, thinking Jacob's ladder for next year.

Did try to build a ghost generator but that is still not up and running.

I think I did mention for home use I filled some latex gloves and left pairs stick out from my front yard...
 
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