# AC vs. DC shock sensation **URL:** \ **Category:** Factual Questions\ **Created:** [December 1, 2008, 3:07pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189 "2008-12-01T15:07:37Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![sweeteviljesus](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@sweeteviljesus](https://boards.straightdope.com/u/sweeteviljesus)\ **Post date:** [December 2, 2008, 10:17pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/21 "2008-12-02T22:17:24Z")
How does anyone get shocked by only 12 volts? Thanks, Rob ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [December 2, 2008, 11:49pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/22 "2008-12-02T23:49:01Z")
> [@sweeteviljesus](#): > > How does anyone get shocked by only 12 volts? Beats me. I would assume you’d feel it if you had breaks in the skin. Or maybe if you were \*extremely \*sweaty. Other than that, not sure. Generally speaking, anything above 50 V is considered an electrocution risk. The higher the voltage (across your body), obviously, the more danger there is. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [December 3, 2008, 1:33am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/23 "2008-12-03T01:33:06Z")
> [@DrCube](#): > > No offense, guys, but I don’t believe you. I haven’t been shocked enough to know firsthand, but if you can’t see the lights flickering, why should I believe you can ‘feel’ the shock flicker? > > I think it is highly more likely that the shocks differed in sensation due to variations in the amount of power supplied to your body, rather than the polarity reversing sixty times a second. If the lights flicker you are never going to know it. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [December 3, 2008, 2:15am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/24 "2008-12-03T02:15:01Z")
> [@Q.E.D](#): > > Because those are two entirely different senses? Sure sure. I’m not saying everybody is wrong, I’m just saying I don’t believe it. To me, ‘feeling’ as a sense has less temporal resolution than sight. Maybe not, though. What kind of frequency do vibrators and other massagers operate at? Because you can definitely feel those. I think 20 frames/second is enough to fool our eyes into seeing continuous motion. I don’t know. I can’t take everyone’s word for it and I’m not going to go experiment on myself. So I guess what I’m saying is… cite? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 3, 2008, 2:24am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/25 "2008-12-03T02:24:16Z")
> [@DrCube](#): > > I can’t take everyone’s word for it and I’m not going to go experiment on myself. So I guess what I’m saying is… cite? [Here, hold this wire…](http://ecmweb.com/mag/electric_working_hot_avoid/) > [@](#): > > _Differences between AC and DC shock._ At 60 Hz, AC produces a slight-to-violent tingling sensation, while DC produces a warm-to-hot sensation. Remember: With DC, only establishing and interrupting the current will cause muscle reaction. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [December 3, 2008, 2:37am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/26 "2008-12-03T02:37:09Z")
You seem to me like exactly the kind of person who’d know the difference. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [December 3, 2008, 2:42am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/27 "2008-12-03T02:42:16Z")
> [@Q.E.D](#): > > [Here, hold this wire…](http://ecmweb.com/mag/electric_working_hot_avoid/) Awesome, thanks. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 3, 2008, 2:49am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/28 "2008-12-03T02:49:41Z")
> [@guizot](#): > > You seem to me like exactly the kind of person who’d know the difference. I assume this means something. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [December 3, 2008, 3:09am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/29 "2008-12-03T03:09:38Z")
> [@DrCube](#): > > No offense, guys, but I don’t believe you. I haven’t been shocked enough to know firsthand, but if you can’t see the lights flickering, why should I believe you can ‘feel’ the shock flicker? I can hear a 60 cycle hum, see a 60 Hz flicker on a CRT and am annoyed by cheap fluorescent lights. Incandescent lights don’t flicker noticeably, but that’s not because the human body can’t perceive a 60 Hz phenomenon. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [December 3, 2008, 3:33am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/30 "2008-12-03T03:33:05Z")
> [@Q.E.D](#): > > Those old magnetos that you used to have to crank by hand to use a telephone were DC. Nope, they were AC. Alinco magnet stationary field, wound armature with sliding contacts (not really slip rings) and no commutator. Phones have been rung with AC pretty much since they have had ringers. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 3, 2008, 3:57am UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/31 "2008-12-03T03:57:24Z")
> [@Kevbo](#): > > Nope, they were AC. D’oh. You’re right, of course. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [December 3, 2008, 5:29pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/32 "2008-12-03T17:29:34Z")
> [@Q.E.D](#): > > I assume this means something. Yes. It means an electrical engineer who has gotten many AC shocks and recently a DC shock really doesn’t need to ask this question. ---
**Author:** ![awldune](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@awldune](https://boards.straightdope.com/u/awldune)\ **Post date:** [December 3, 2008, 6:40pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/33 "2008-12-03T18:40:01Z")
> [@sweeteviljesus](#): > > How does anyone get shocked by only 12 volts? > > Thanks, > Rob If this was directed at me, I was very sweaty and it was my forehead that touched the battery terminal. The terminal might also have had vaseline on it. I was removing the metal bumper mount on my car, and was probably grounded reasonably well. ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [December 3, 2008, 8:48pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/34 "2008-12-03T20:48:33Z")
> [@](#): > > I can hear a 60 cycle hum This is highly unlikely, human sensitivity of hearing drops off below 100Hz quite dramatically. You can hear such frequencies directly but the sound levels have to be very high indeed. What you highly likely can hear is the first harmonic, 120Hz which is well inside your hearing range, you may also hear other harmonics which when reacting with each other can produce sounds lower than your 120Hz. The 60Hz flicker is usually only visible due to the strobing effects against other devices which operate slightly out of phase but at or very near the same frequency. On very badly depleted phosphors and fluorescant materials where persistance is extremely short then you might just see some flicker, but such low persistant materials have largely been relegated to history. Mostly these irritations are something our brains recognise as a pattern in comparison to something else rather than in their own right. Worst shock I ever had was only 50V, but I was stripping back telephone cable, with my teeth, up a crane 50 feet up and I dared not let go of anything, very interesting experience. I’ve had much higher voltage shocks, which comes from working with valves, tvs and stuff like that, but that 50V was still the worst. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [December 3, 2008, 11:26pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/35 "2008-12-03T23:26:00Z")
> [@casdave](#): > > Worst shock I ever had was only 50V, but I was stripping back telephone cable, with my teeth, up a crane 50 feet up and I dared not let go of anything, very interesting experience. > > I’ve had much higher voltage shocks, which comes from working with valves, tvs and stuff like that, but that 50V was still the worst. I though it was 49 volts. No big difference. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 3, 2008, 11:31pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/36 "2008-12-03T23:31:34Z")
> [@guizot](#): > > I though it was 49 volts. No big difference. It’s 48 V nominal, actually. But, the actual voltage can range around that value by several percent. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 3, 2008, 11:36pm UTC](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189/37 "2008-12-03T23:36:35Z")
> [@casdave](#): > > What you highly likely can hear is the first harmonic, 120Hz which is well inside your hearing range, you may also hear other harmonics which when reacting with each other can produce sounds lower than your 120Hz Actually, most of what people call “60-cycle hum” is in fact 120 Hz hum. The hum is generally caused by either magnetostriction in transformer or inductor cores or by magnetic repulsion/attraction in adjacent conductors. Both of these effects complete two full cycles for every one electrical cycle. [Previous page](https://boards.straightdope.com/t/ac-vs-dc-shock-sensation/475189.md?page=1)