My question is about how dangerous a momentary amount of current is vs the duration.  Like is there a reasonably consistent relationship between current duration through the body and relative danger?  I.e. 1 amp for 1 second vs 0.01 amps for 100 seconds.  I imagine that's a bit complex to determine, but otherwise is there a duration for which a normally deadly amperage would shock someone but not cause a heart attack?  I read an article about research into a possible electric weapon that would shock someone on the scale of nanoseconds to stun them without risking killing them.
122904
I have a few circumstances which invlove someone being shocked with 20 watts of electricity and whether it would be deadly. So here they are:   Would 1000 volts at 20 miliamperes of AC (2MHz frequency) be dangerous or deadly? Would 1000 volts at 20 miliamperes of DC be dangerous or deadly? Would 10 Kilo volts at 2 miliamperes of AC (2MHz frequency) be dangerous or deadly? and Would 10 Kilo volts at 2 miliamperes of DC be dangerous or deadly?   Thanks for everyones help.
24994
Electricity takes the path of least resistance!   Is this statement correct?    If so, why is it the case?  If there are two paths available, and one, for example, has a resistor, why would the current run through the other path only, and not both?
57038
This is blowing my mind.  Let's say I've a bunch of 100 Ohm resistors, all identical.  How is it possible that if I combine them in parallel, I can get something that has less resistance?  Check this out:     ----100OHM--- ---|           |---    ----100OHM---   This is effectively a 50 Ohm resistor!  It was already hard for current to get through one resistor (at 100Ohms), but I combined two resistors together, and now it became easier for current to go through!  If I take ten 100 Ohm resistors in parallel:  Check this out:     ----100OHM---    ----100OHM---    ----100OHM---    ----100OHM---    ----100OHM--- ---|---100OHM--|---    ----100OHM---    ----100OHM---    ----100OHM---    ----100OHM---   This is now 5 Ohms!!!!!!!!!!!!!!!!!!!!!!! Electricity is no longer having almost any resistance, yet each of resistors is 100 Ohms. If I added even more 100 Ohm resistors, resistance would go close to 0, and current would just flow through with no resistance.  How is that even possible? If I think logically, then it could only have gotten HARDER for current to go through two resistors, but somehow it became easier.  Real life analogy:  Let's say there's a 500 pound bouncer at club entrance. It's hard to get past him right? He's strong and will resist you getting past him. Now if the club adds another bouncer at 500 pounds, it suddenly becomes EASIER to get past both of them??  There's no way it's possible!! Can anyone explain this in simple terms?
3891
I recently came to know about the Conventional Current vs. Electron Flow issue. Doing some search I found that the reason for this is that Benjamin Franklin made a mistake when naming positive and negative charges. There is even this little comic about that   My question is, how can a naming convention be wrong? Perhaps I don't understand what is the actual mistake here, I don't know. But I don't see how a naming convention could be wrong or right. There is no right and wrong about that. It could've been any other name, like charge A and charge B.  I'll appreciate anyone can help me understand what is wrong in all this.
88452
I came across this statement while studying electric currents and I am confused:  "There is no electric field inside a conductor. Hence no current can flow through it".  Is there a fallacy in this statement?  Any help would be appreciated.  The conductor being discussed is ideal. What is the driving force for the current in this case?
34240
The situation is this.. I am performing a photoelectric effect experiment - just the usual - evacuated glass tube containing two metal electrodes connected to an external source of DC voltage (say an alkaline cell) and ammeter in series. I shine a light on one of the electrodes - the frequency is more than enough to cause eject photoelectrons, and the voltage of the cell opposes the electrons which are trying to get to the other electrode. The question is this - what happens to the current on increasing the intensity of light while keeping no. of photons falling on the electrode constant (in other words increasing the frequency)?   Does the current remain the same because the no. of photons falling on the electrode is constant and so no. of electrons being ejected is constant? Or does it increase because the electrons have more kinetic energy, ie, they are moving faster towards the other electrode so that the $t$ (time) term in $I$ = $q$/$t$ is less ($q$ remains constant because no. of electrons being ejected is still the same)?   This question appeared in one of my tests and the answer key says that the current remains constant but think that case 2 is correct and current would increase, which is why I asked this question.  Thanks.
28037
If current is the rate of flow of electrons past a point. Let's say a wire is full of electrons, and of course they pretty much are already going the speed of light, minus friction. What would increasing the voltage do?   You can't go faster than the speed of light, and you can't increase the rate of electrons because no more fit in the tube. I am just curious what this would look like. I feel like I am missing a key concept.
74083
I understand when we say current, we mean charge (protons/electrons) passing past a point per second. And the charges have energy due to the e.m.f. of the power supply.  Now tell me, if a lamp has resistance and you hook it in the circuit, how will the current stay the same? The charges obviously lose energy in the lamp and so become SLOWER, which should mean current decreases, right?  [Edit] All answers explained a bit of everything, so it was hard to choose one. If YOU are looking for an answer, please check the others too, in case the accepted one doesn't answer your question.
116345
What's the point below which electrical current is generally considered safe for "casual" human contact?  Is either voltage or amperage more "dangerous" (e.g. high voltage / low amperage vs. low voltage / high amperage), or is the only consideration the total current?
75903
If I am thinking of replacing a light switch, a light-fitting, a socket/outlet or doing other work with household wiring where there may be 120 Volts or 240 volts present ...  There is already a question on  which is mostly about procedures but ...  what types of tools are available for testing that wires are safe and, as an average householder, which type of tool should I buy to help avoid electrocution?
46410
I get confused on the low-level physics of electricity from time to time. It came up in "," and I don't totally get it.  How fast does electricity flow? Is the speed of an electron different in say a resistor than in a wire? Does it matter? Or are the effects of the electron the only important thing, with lower levels of abstraction not useful in practice?  I know there are already materials on this topic, and I have read some of them. I think having the question on this site might inspire some interesting answers to the age-old question.  Bonus points for:   Identifying and clearing up common misconceptions Explaining in a way that someone with a high school diploma could understand, without oversimplifying it so much that its incorrect
107952
In the link below, this circuit I found is what I needed. Only the length of the pulse and the delay are not what I want.  When I want just 0.5sec before pin 3 is up and the pulse duration I want is also 0.5sec, can someone tell me how big my resistors and capacitors must be? Or can someone tell me how I can calculate this?  My source power is 16 Volts I have already found 555 timers that can operate with 16 Volts, so thats not the problem.  When someone has another idea with two 555-timers, or something else that does the same, it's also OK.  Thanks
13691
If the neutral wire carries current, why do many people believe that it's safe? I've heard "You can touch the neutral wire/bar in the breaker box and not get shocked. Only the hot can hurt you." If the circuit is complete and current is flowing, can't you receive a shock?
105960
I see every day high voltage, high current; high voltage, low current. I rarely see low voltage, high current; why?  I know that I can take a high voltage, high current signal, send it through a step-down transformer and theoretically get a low voltage high current (with the same power output, of course), but I never see this done.  Can someone give me a reason as to why I wouldn't want a low-voltage high-current scenario?
114766
If we assume a short circuit, with zero resistance (not even within the battery), would this 'infinite current' deplete all voltage within the battery? For example, if I "short" a 9V alkaline battery, it will run for about an hour (though the wire gets pretty hot, if not melts) until it depletes all its power. Is this only because the battery has internal resistance, or why does the battery 'keep running'? Additionally, does a battery ever give its Amp-hours or how long it can run?
25089
I'm looking for guidelines on how to identify capacitors which have the potential to cause pain, injury or death due to electrical shock if not handled correctly.  I recently purchased a "getting started with electronics" kit from Radio Shack. It contains an electrolytic capacitor of 1,000 µF and 25 V. I'm assuming this particular capacitor doesn't have the potential to cause such harm because it was included in an introductory kit. However, at what point does a capacitor have the potential to cause pain, injury or death due to electrical shock?  Ideally, I'd like links to reference material on the subject.
23555
We all know that the amount of current flowing b/w the plates is independent of the frequency. If I were to ask why doesn't it depend then you'd probably say that it depends on the number of electrons rather than the frequency or you might show me a current vs frequency graph.  But here is my theoretical argument. Electric current is defined as the amount of charge flowing through a point/space/wire per unit time. Let I be current due to photo electrons ejected by photons of some frequency. Now if I would increase the frequency, the kinetic energy of the ejected electron would increases, therefore it will move faster and therefore contribute more current (charge will through the same point many times per unit time) . Thereby, giving a net current greater than I.  What is wrong with my argument?  After thinking a lot, I came up with a possible reason. However fast the electrons may move, but when they hit the metal plate, they would lose their velocity and start moving in drift velocity. Now there is a problem with this argument. If this were to be true then I should expect to see a big chunk of extra electrons getting stuck at the anode.  If my reasoning was correct, then why can't I see a big charge buildup at the anode.