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Electric shock from USB cable
crabby3:
I've experienced this can't let go and it's scary. Screw gun on a construction site. Couldn't let go of the trigger or open my hand.
Had to swing my arm, like throwing a frisbee, to make the tool pull away. This was back when electric tool housings were metal and heavy.
My arm was still tingling as I stepped out of the puddle.
In retrospect I probably could have just stepped out of the puddle but it didn't occur to me at the time. Not gonna test it. Once is too many.
Stupidity of youth. ;D
Vurbal:
The last digit on a digital measurement device is always wrong. Wrong as in not accurately showing the true value, only the approximate one.
Although analog meters do not have this problem, they have their issues as well. Normally these cannot be trusted on both the (extreme) low and (extreme) high values. Most analog meters are created to show measurement values accurately on a selected part of their full scale.
-Shades (January 15, 2013, 01:53 PM)
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This is an even bigger problem in lower quality devices when the precision ends up being more than the accuracy of the measurements.
When I was taking electronics classes I was fortunate enough to acquire a Fluke 77III. One day a friend and I decided to compare the measurements from his hobbyist meter against my Fluke by measuring the voltage drop across a diode - something in the order of a couple hundred mV. His meter gave a slightly different measurement every time and they were all at least 30% higher than the consistent number from the Fluke.
More recently I've noticed the same problem when buying a kitchen scale. Unless you find one where the manufacturer lists an 'internal resolution', you can safely assume the accuracy is equal to the precision. To make matters worse, scales made for the US market are typically accurate to a tenth of an ounce but also have an option to display grams. Of course 0.1oz is approximately 2.8g so the real precision is effectively reduced by another digit.
Sadly most people don't even understand the difference between accuracy and precision, let alone how one affects the other.
Analog car speedometers, fuel and heat gauges are famous examples of this principle. It is actually very costly to make an analog meter that works well all over its scale.
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Analog meters have another problem relative to modern electronics. You can't always distinguish sudden and gradual changes reliably.
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