On 10/25/2014 07:49 AM, Patrick Shanahan wrote:
- ellanios82 <ellanios82@gmail.com> [10-25-14 10:41]: [...]
re : "makes me VERY nervous when replacing them" . . . would reason be risk of electric shock? more likely burn. One is very unlikely to get "shock" from dc current, but availability of instantaneous high current greatly increases burn hazard.
I respectfully disagree! Direct current is even more dangerous than alternating because the DC will "freeze" your muscles which could prevent you from releasing the thing shocking you. AC will cause your muscles to "twitch", making it easier to drop the hazard. I remember an old-school EE who said he could "taste" a battery terminal and tell you if it was positive or negative. He demonstrated this remarkable feat with a 9-volt transistor radio battery with both terminals on one end. So his tongue closed the circuit between the terminals and you should have seen that battery fly across the room at Mach-3! This experience and others, prove that very smart people, who are very specialized, can be really stupid outside of their fields. For example, I once had a bet with this same EE who claimed that it was impossible to tell the difference between a sound in front of you and one behind you. His argument was that there is a 180-degree directional ambiguity when you have only two sensors. I told him that there are other ways to localize sound directionality, but he wouldn't believe me. So I sat on a chair with a blindfold and he snapped his fingers wherever he wanted around me and I was able to point directly at the sounds. I was able to differentiate all three axis, pointing up and down as well as front and back without moving my head. I won the bet. The shape of your ears and reflections from walls and ceilings make it easy to differentiate. What was amazing is this guy was in his late '50s and hadn't figured all this out for himself! Regards, Lew -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org