Post
by juice » Mon May 07, 2007 12:23 am
me:
while young:
luckliy put key in the wrong (well, I guess the right, since I am here) hole a couple of times
older:
tried to make tazer out of disposable camera, succeeded, broke prototype upon initial test, threw it across the room.
A little older:
aided in the shock of a student in a physics class. We found this cool electric chain thing used for an experiment to study momentum. It lit up this cathode tube we had real good, unfortunately the chain also wrapped around fellow student's hand. Seeing someone holding on to a chain at 120v for 4 seconds is both funny and very scary.
a couple of years ago.
fender bronco with a bad tube (don't remember which one), no 3 prong cable, and no knob on the potentiometer. I had a jolty good time turning up the volume.
I have a coworker with an 8 inch scar on his scalp from being hit by lightning while hiking.
Using latex gloves is a good idea if you are new, especially if your projects don't work when you first fire them up. After the fender champ thing I am so paranoid about ungrounded equipment.
Also, never underestimate the stupidity of a someone who came before you, especially in "finished" basements.
Here are some numbers from the internet:
The conditions necessary to produce 1,000 Ω of body resistance don't have to be as extreme as what was presented, either (sweaty skin with contact made on a gold ring). Body resistance may decrease with the application of voltage (especially if tetanus causes the victim to maintain a tighter grip on a conductor) so that with constant voltage a shock may increase in severity after initial contact. What begins as a mild shock -- just enough to "freeze" a victim so they can't let go -- may escalate into something severe enough to kill them as their body resistance decreases and current correspondingly increases.
Research has provided an approximate set of figures for electrical resistance of human contact points under different conditions (see end of chapter for information on the source of this data):
* Wire touched by finger: 40,000 Ω to 1,000,000 Ω dry, 4,000 Ω to 15,000 Ω wet.
* Wire held by hand: 15,000 Ω to 50,000 Ω dry, 3,000 Ω to 5,000 Ω wet.
* Metal pliers held by hand: 5,000 Ω to 10,000 Ω dry, 1,000 Ω to 3,000 Ω wet.
* Contact with palm of hand: 3,000 Ω to 8,000 Ω dry, 1,000 Ω to 2,000 Ω wet.
* 1.5 inch metal pipe grasped by one hand: 1,000 Ω to 3,000 Ω dry, 500 Ω to 1,500 Ω wet.
* 1.5 inch metal pipe grasped by two hands: 500 Ω to 1,500 kΩ dry, 250 Ω to 750 Ω wet.
* Hand immersed in conductive liquid: 200 Ω to 500 Ω.
* Foot immersed in conductive liquid: 100 Ω to 300 Ω.
Note the resistance values of the two conditions involving a 1.5 inch metal pipe. The resistance measured with two hands grasping the pipe is exactly one-half the resistance of one hand grasping the pipe.
