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Electrical Safety. U.S. PRESIDENTS. “OHM” MY!. ELECTRICAL SAFETY. VIVE LE RESISTANCE. 30 KV ABOVE GROUND. “U.S. PRESIDENTS FOR $600 PLEASE…”. WHO WAS PRESIDENT WHEN ELECTRICITY WAS INSTALLED IN THE WHITE HOUSE?. BENJAMIN HARRISON. Vive Le Resistance for 400 please.
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U.S. PRESIDENTS “OHM” MY! ELECTRICAL SAFETY VIVE LE RESISTANCE 30 KV ABOVE GROUND
“U.S. PRESIDENTS FOR $600 PLEASE…” • WHO WAS PRESIDENT WHEN ELECTRICITY WAS INSTALLED IN THE WHITE HOUSE? BENJAMIN HARRISON
Vive Le Resistance for 400 please • What is the canonical value of resistance for a human gripping two tips of a multi-meter? • 500 kW
Principle 1: You’re a salty bag = R I’m a resistor; you’re a resistor! Hooray, we’re all resistors! 2013 Circuit class resistance (gripping tips of ohmmeter probes with dry skin): Mean +/- std. dev 1.3 +/- 1 Mohm Range: 105 kOhms – 3.2 MOhm Canonical value: 500 kW (a reasonable ‘back of the pocket’ number to carry around)
Is your resistance always the same? Franco Colombo on Venice Beach circa 1960
“ALEX, I’LL TAKE OBSCURE ENGINEERING HISTORICAL FIGURES FOR $1000 PLEASE • WHAT UNIV. OF CALIFORNIA PROF STUDIED THE EFFECTS OF ELECTRICAL CURRENT ON ELICITING INVOLUNTARY MUSCLE MOVEMENT WHO LATER INVENTED THE GFCI? CHARLES DALZIEL CHARLES DALZIEL
Principle 3: Earth is a Conductor • “Don't think it's conductive? Go stand outside in your bare feet and hold a hot wire. But before you do make funeral arrangements.” -Bill Marsden
Lil Birdie • Is the bird shocked? • Why or why not? • Draw the circuit diagram and explain
The Third Prong Never ever remove it!
How the 3rd prong could SAVE you Hot wire in contact with metal case due to wear over time
Hollywood + Circuits: Fact or Fiction? Can a toaster dropped into a bathtub electrocute you?
Is Ken toast? Crap….I dropped my toaster in the bathtub again Develop an approximate circuit model a person soaking in a bathtub with an electrical appliance in contact with the water, then…
Shock Therapy: Tough Mudder "I figured if I had the stamina to run four marathons, I could take the brunt a good-humored 10,000 volt shock. Not quite. "The obstacle, the last of a few dozen, was 50 yards from the finish line. What made it worse: There was a wait. A line formed so we could watch people run through 50-60 dangling wires that charged with electricity every three seconds… "When it was my turn, I took off fast hoping to power my way through. "The first shock hurt like hell. If you've ever been shocked before, you know how it feels. Intense pin-prickling pain is followed by your extremities involuntarily flailing in all directions. "The second shock just about sent me to the ground. Mind you, we were running over hurdles of dirt through the 20 feet of live cables. I almost made it until the third shock hit. My legs left the ground and sent the rest of my body face first into the wet mud.
Image Sources/Citations • http://howelectricityworks.weebly.com/ • http://science.nationalgeographic.com/science/photos/heart/ • http://www.physics.ohio-state.edu/~p616/safety/fatal_current.html • allaboutcircuits.com • Loyalkng.com • http://www.aikencolon.com/Fluke-1630-Earth-Ground-Clamp-Meter-Tester-Test-Equipment_p_3119.html • http://www.youtube.com/watch?v=PXvCLMcFVBY&feature=related (bolt of lightning) • http://toughmudder.com/obstacles/electroshock-therapy/