I went to a power supply design seminar last week.
I got some useful information about safety. This handy chart was in the book we got:
THRESHOLD VALUES OF ELECTRICAL CURRENT Current (mA) Effect 0.0 to 0.5 Perception, minimal reaction 0.5 to 3.5 Startle Reaction, but ability to tolerate 3.5 to 10 Muscles contract, inability to let go 10 to 50 Fibrillation, cell damage
Now, current happens because of voltage. For safety, regulations say we need to prevent people from coming in contact with anything that would generate more than 2.0 mA of DC current. They recommend protecting anything higher than 43V peak ac or 60V dc.
Just so you know. Stay away from those 110vac outlets, which are actually something like 170 pk vac.
And how do we know a 110vac outlet when we see one?
Or is this just a fancy way of telling us not to stick our fingers in light sockets?
It’s a fancy way of telling you not to put your fingers in light sockets, or those regular sockets in your wall (which are 110vac).
If you think the impulse to do so might be too strong, we can loan you some of those child plastic plugs you can stick in them.
Should I stop licking extension cords too? I mean how else am I supposed to tell if the other end is plugged in behind the couch?
Seriously though, I have touched both 110 and 220 circuits. It *will* get your attention. I don’t recommend it.
So is it still safe to touch 9v batteries to my tongue?
The 9V-on-the-tongue question has always bothered me.
You can put a 9V on your arm, but you don’t feel it. But if you put it to your tongue, you surely do. I believe that means that your tongue is more conductive than your skin, which would mean you get more current through your tongue than skin. So the rule-of-thumb from the seminar don’t apply.
However, there’s no chance of the 9V going through your heart and wreaking havok, but you might lose a taste bud or two.
Still, it’s a quick way of telling if they’re any good… 🙂
Lets go about it scientifically!
What are the differences between the surface of your tongue and the surface of your arm?
1) Arm is hairy, tongue is not (usually). Probably not relevent, unless your arm is REALLY hairy, enough to provide insulation.
2) Tongue has tastebuds, arm does not. Again, probably not relevent, it is not the chemical content of the terminals that we are detecting.
3) Nerve endings more densely packed on tongue than arm. Well, that would seem to imply a reduced sensitivity, not an atomic change.
4) Tongue is wet with saliva, Arm usually is not. Hmm, that could be it. licks arm, applies battery, ah! Yup, that seems to be it, milder zap, but still a zap.
So, to feel the zap, the skin patch touched should be dense with nerve endings and moist. Further research seems possible, but will not be pursued at this time.
I am always needing information of just this sort, given my proclivity for wiring things about the house. Which reminds me that I need to get the smoke detector out of the refrigerator and wire it back into the ceiling where it belongs.
Because I pay attention to these seemingly random chunks of useless information,
Do I know you?
If they don’t want you to lick electrica outlets, they should stop making them in such delicious fresh fruity flavors.
No really, they are. Most older households outlets have strawberry on the top socket and banana on the lower ones. A lot of developers have started adding new flavors too like Pina Colada and Tiramisu as added selling points.
I swear to god. Try it!
You should be illegal.
No, he should be widely published. With demonstrative illustrations.
There simply are not enough leopards roaming the streets of America to prevent the weak members of the human herd from breeding. is just filling their role.
If you do try it and don’t taste the strawberry, don’t get discouraged. In older houses, the flavor has worn off the front of the outlet, but there’s still plenty of tasty goodness inside. Try sticking a fork or knife in there to scrape some out to the front.