I understand the TV sci-fi tendency to "reverse polarity" with equipment is not a good idea in real life.

Kor

Person with problem complains to the Doctor (Jon Pertwee) on the phone.

Third Doctor: "Have you tried reversing the polarity of the neutron flow? You have, and it still doesn't work? Sorry, old chap, you're on your own, then. I'm fresh out of technobabble."

I still love the conversation between the 10th and 11th Doctors in The Day of the Doctor when they both try to reverse the polarity at the same time.

"We're confusing the polarity!"

The hand-me-down Windows laptop I got from my sister, while mostly a very good laptop, bizarrely has a symmetrical, unpolarized plug on its charger, and if you plug it in the wrong way, the metal case gets mildly electrified and you feel a faint electric buzz if you touch it. So that's an example of a problem that is solved by reversing the polarity. Although I guess it's more accurate to say it's a problem that was created by making the polarity reversible in the first place. (I marked one side of the plug so I know which way it should go in, though mostly I just leave the charger plugged into the outlet permanently when I'm at home, for convenience.)

That... shouldn't happen. Granted my electrical knowledge is that of a hobbyist using batteries, not AC mains, but to my understanding neither of those lines should be grounding to the case. It strongly suggests there's a damaged wire somewhere inside the charger.

No, I looked into it, and apparently it's a common problem with this model of laptop. It might have to do with the way the cable connects to the laptop, which isn't a standard jack but a rectangular tab that attaches magnetically to a slot in the laptop. And it's not specific to one charger; my sister sent me two, and it happens with both of them. Also, I tried buying more robust power cords than the ones that came with the chargers, believing that they would be polarized, but they weren't. And it happens with them too.

The police can, and often do, arrest you even if you weren't read your Miranda warnings.
The District Attorney can, and often does, get a conviction even if you weren't read your Miranda warnings.

How wildly inaccurately tv and films use defibrillators could probably be worthy a thread all of its own.

How wildly inaccurately tv and films use defibrillators could probably be worthy a thread all of its own.

Emergency! used to be fairly good with the use of defibrillator in the early days.

The hand-me-down Windows laptop I got from my sister, while mostly a very good laptop, bizarrely has a symmetrical, unpolarized plug on its charger, and if you plug it in the wrong way, the metal case gets mildly electrified and you feel a faint electric buzz if you touch it.

Actually, that's not a matter of reversing polarity (AC has no permanent polarity; its polarity reverses [in North America] 60 times per second, on a sine wave), but reversing polarization. In the North American standard for power distribution, the standard domestic single-phase power comes off of a center-tapped 240VAC secondary of a step-down transformer, with the center-tap tied to ground (the round third prong is a redundant safety ground, independently tied to ground). This puts each hot lead at 120VAC relative to ground, and 240VAC relative to the other hot lead.

Before polarized power plugs became standard, it was entirely possible for the unswitched shell of a lamp socket, or the unswitched chassis ground of a "hot-chassis" vacuum-tube radio or TV, to be energized at 120VAC, whether the switch was on or off. The purpose of plug polarization is to ensure that this doesn't happen.

Emergency! used to be fairly good with the use of defibrillator in the early days.

Actually, that didn't change; the technology changed. When Squad 51's defibrillator and EKG monitor were upgraded to a model (the Datascope MD2) that stored the monitor in a docking station on the defibrillator (around season 3, as I recall; the newer monitor had a scrolling display, rather than a flying point display), the monitor gained a "read-through-paddles" function when docked: one position on the lead-selector dial selected this function. If you had a good memory, you might recall that Gage or DeSoto would occasionally apply the paddles to the patient's torso, and look at the monitor screen, If it showed V-fib, the paramedic would then hit the charge button, and apply conductivity paste to the paddles, before defibrillating the patient. When field-stabilizing a patient who could have been in V-fib for some time, the minute you didn't spend attaching monitor leads to the patient could mean the difference between saving and losing the patient.

This read-through-paddles function, of course, is what makes the automation in an AED work.

Disclaimer: I am not a doctor, nor a paramedic, and neither do I play one on television. But I will note that on an EKG monitor, set to Lead II, anybody should be able to recognize the basic patterns of sinus rhythm, ventricular tachycardia, and ventricular fibrillation. Maybe even spot premature ventricular contractions before the automation in modern EKG monitors does.

Before polarized power plugs became standard, it was entirely possible for the unswitched shell of a lamp socket, or the unswitched chassis ground of a "hot-chassis" vacuum-tube radio or TV, to be energized at 120VAC, whether the switch was on or off. The purpose of plug polarization is to ensure that this doesn't happen.

Yes, I read that when I looked into the issue regarding my laptop charger. Apparently there were instances of people being electrocuted by lamps or the like. That's why I'm so surprised that Microsoft in this day and age is making unpolarized plugs.

More than that, if there's a reason for some electronic device with a "wall-wart" or other external power supply to be grounded, then that external power supply should have a 3-prong plug.

I don't have enough of an electrical engineering background to fully understand how switching power supplies work, but I've built enough linear power supplies over the years to know that at least with linear, the low-voltage output is 100% isolated from both sides of the line voltage input. And I also know that for a given wattage, a linear power supply is going to be much bulkier, heavier, and more expensive than switching.

If you are innocent of a crime, you do, in fact, need a lawyer, and you do have something to worry about.

Christopher Nolan himself admits that the "Rub your chest, your arms will take care of themselves" bit from Batman Begins is just something he made up. So please don't do it.

If you are innocent of a crime, you do, in fact, need a lawyer, and you do have something to worry about.

And beyond the basics, you should absolutely remain silent.

Emergency! used to be fairly good with the use of defibrillator in the early days.

Jack Webb shows tended to be corny as all heck but they tended to get the details of the main characters' jobs pretty correct.

Yes, I read that when I looked into the issue regarding my laptop charger. Apparently there were instances of people being electrocuted by lamps or the like. That's why I'm so surprised that Microsoft in this day and age is making unpolarized plugs.

Well if they put quality control before profits they wouldn't be doing capitalism correctly.

Well if they put quality control before profits they wouldn't be doing capitalism correctly.

That's the thing -- the laptop itself works great. It's just the chargers that are weird.