Tweakers' Asylum

1kV won't jump very far at low altitude.

71.231.229.130

Ugly

In Reply to: RE: That's what 10X and 100X probes are for. posted by fmak on May 14, 2009 at 21:49:32

Even at 30kV, the max my ESD gun could generate, I was only getting somewhere around a half to full one inch arcs. If you live on the peak of mt everest or in a high atmosphere weather balloon though you might want to take a little more precaution depnding on 1kV source output impedance. ;-) The ESD gun was based on human body model and just caused a pinch feeling in my toe when I tried discharging through it @30kV but it made the beatle crawling across the ESD bench quit moving when he got used as the path to ground.

Follow Ups:

RE: 1kV won't jump very far at low altitude. - fmak 04:07:21 05/16/09 (2)
One is brave when young.

It is not voltage but curent to ground that kills; 5 mA thru the heart and you are dead.

Scope probes are not reliable, even expensive ones. One careless error, and it can really hurt.
- RE: 1kV won't jump very far at low altitude. - Ugly 10:46:03 05/17/09 (0)
  "One is brave when young."
  
  Well, I happened to have the specs for this equipment and it is based on the human body model which means it only supplies a very limited amount of charge for each discharge then it's spent until recharged...something like 10's of pico farrads. Besides, it's just a toe. I have four more on that foot. Luckily the toe is fine.
  
  "It is not voltage but curent to ground that kills; 5 mA thru the heart and you are dead."
  
  I'm well aware of this and so very carefully made my selection of body parts to ionize.
  
  "Scope probes are not reliable, even expensive ones. One careless error, and it can really hurt."
  
  In general I'm not very comfy working around high voltages but in this case allowed my ability to engineer a non deadly self experiment combined with a great curiosity of the unknown and flat out boredom to overcome my fears of whatever pain, disfigurement, or loss of life that might be the result. The QA dude was standing there watching and thought I was insane. You might say it was necessary to put full trust in my understanding of the physics involved in order to work up the nerve. I precisely predicted the results of the experiment before carrying it out adding to my confidence in my understanding of how ESD will occur. Trust in the theory grasshopper.
- not reliable? - Tweekeng 09:31:55 05/16/09 (0)
  Scope probes are not reliable, even expensive ones. One careless error, and it can really hurt.
  
  Sure if you are careless you can be hurt walking down a hallway.
  
  How do you think high voltage devices like switching power supplies are designed and tested? Somebody somewhere had to put a scope on it and make sure it's working right.
  
  I have not seen anyone get injured by a scope probe's insulation failing.
  
  I have see scope probe ground leads vaporize. But this is most often due to using a grounded scope when a signal ground has a large voltage potential above or below Earth ground.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable