3 ms·

Well... one difference between a stun gun and CRT tube is that in a stun gun you usually have both terminals relatively close to each other. Little chance of th

Well... one difference between a stun gun and CRT tube is that in a stun gun you usually have both terminals relatively close to each other. Little chance of the main pulse going deep across the chest. On the other hand working with the CRT you are likely using both hands and that makes the signal go through your upper chest, by default. So yeah, there is something to it. One thing I learned as amateur EE is to always use just one hand to probe the device under test if there is any high voltage or AC involved. You put the other hand behind you so that there is no chance you create a short right through your chest.

Scoundreller 3y ago
And have someone nearby with a 2x4 to beat you off whatever you might be gripping/fell onto.
- sowbug 3y ago
  Just to add a bit more color here: most flexor muscles in your body are a lot stronger than the corresponding extensors, so when an external command comes in telling both to contract, for example from electricity in the thing you're working on, gripping wins. You can't let go. Great for grabbing a branch as you fall out of a tree. Not so great for repairing a power line. Late edit: I've heard you can use this factoid to your advantage to avoid being eaten by an alligator or crocodile. Wrap your arms around its snout and hold on for dear life. Their jaws are strong enough to snap you in two, but not enough to force themselves open when you're holding them shut. I don't know what Step Two is, unfortunately.
  - jareklupinski 3y ago
    > I don't know what Step Two is, unfortunately. step two is waiting for the aforementioned 2x4 wielder "to beat ... whatever you might be gripping/fell onto"
    - rzzzt 3y ago
      "Mother" on speed dial maybe?
  - hallway_monitor 3y ago
    The bit about holding an alligator's mouth closed is correct and I remember Step Two from an alligator wrestling demonstration: flip it over. They lose consciousness if you can hold them in an inverted position.
    - HeyLaughingBoy 3y ago
      So do chickens, but they're a lot easier to wrestle.
  - TFortunato 3y ago
    Related fun fact - On many industrial robots that I've worked with, the teach pendant (the handheld controller you drive it around with), requires you to hold a 3 position spring-loaded switch in a middle position for the robot to operate, which requires you to hold with a rather precise amount of force. Squeeze it either too loosely or too tightly and the robot disables. The idea being that not only will you dropping the pendant disable the robot, but it will also disable if you accidentally touch energized equipment and your hand clenches, or (more likely) you panic and squeeze the controller too tightly. https://us.idec.com/idec-us/en/USD/Safety-Components/Enabling-Switches/c/Enabling_Switches https://us.idec.com/idec-us/en/USD/Safety-Components/Enablin...
close04 3y ago
> One thing I learned as amateur EE is to always use just one hand to probe the device under test I was taught to use the back of my hand to avoid gripping the damn thing and never letting go.
- renewiltord 3y ago
  Same. And I do it like a superstition now.
mauvehaus 3y ago
You're describing the well-known Alanis Morissette technique for electrical work: "I got one hand in my pocket, and the other one holding a DMM"
dmoy 3y ago
> One thing I learned as amateur EE is to always use just one hand to probe the device under test if there is any high voltage or AC involved. I remember in some EE course, the prof randomly stopped in the middle of a lecture and said roughly "Ok now that you all know this theory, I need to remind you that you should not go do your own home electrical work, because you will get ahead of yourself and die from some kind of electric shock" The implication being: 1. You're trained, but for EE not electrician work 2. You'll think you know what to do, even if you don't it'll cloud your judgement 3. As an EE you will make enough to pay a real electrician to do your electrical work Needless to say in the real high power EE courses (t lines, grid, etc), this wasn't even mentioned, because it was just implicitly known that all that stuff was in the realm of "Don't physically touch this stuff in the real world ever because it will kill you and it will hurt the whole time you're dying".
- onetimeuse92304 3y ago
  I did not mean doing home electrical work. That I do leave to professionals. But there are times I have a device on my bench that is consuming 230V AC. I have a 3kVA separation transformer set up, which makes it safer for me to work with the device (there is no potential between the DUT and the ground). Technically, even without the transformer the residual current protection should kick in and prevent you getting killed between device and the ground. I have tested mine couple of times to check whether it works. But I somehow still feel better with a separation transformer. But there is still the problem that I could touch different parts of the device that are at different potential and then I could get zapped this way. There is not much protection there. Solution -- If you must, don't ever touch more than one place at a time.

Scoundreller 3y ago

And have someone nearby with a 2x4 to beat you off whatever you might be gripping/fell onto.

sowbug 3y ago
Just to add a bit more color here: most flexor muscles in your body are a lot stronger than the corresponding extensors, so when an external command comes in telling both to contract, for example from electricity in the thing you're working on, gripping wins. You can't let go. Great for grabbing a branch as you fall out of a tree. Not so great for repairing a power line. Late edit: I've heard you can use this factoid to your advantage to avoid being eaten by an alligator or crocodile. Wrap your arms around its snout and hold on for dear life. Their jaws are strong enough to snap you in two, but not enough to force themselves open when you're holding them shut. I don't know what Step Two is, unfortunately.
- jareklupinski 3y ago
  > I don't know what Step Two is, unfortunately. step two is waiting for the aforementioned 2x4 wielder "to beat ... whatever you might be gripping/fell onto"
  - rzzzt 3y ago
    "Mother" on speed dial maybe?
- hallway_monitor 3y ago
  The bit about holding an alligator's mouth closed is correct and I remember Step Two from an alligator wrestling demonstration: flip it over. They lose consciousness if you can hold them in an inverted position.
  - HeyLaughingBoy 3y ago
    So do chickens, but they're a lot easier to wrestle.
- TFortunato 3y ago
  Related fun fact - On many industrial robots that I've worked with, the teach pendant (the handheld controller you drive it around with), requires you to hold a 3 position spring-loaded switch in a middle position for the robot to operate, which requires you to hold with a rather precise amount of force. Squeeze it either too loosely or too tightly and the robot disables. The idea being that not only will you dropping the pendant disable the robot, but it will also disable if you accidentally touch energized equipment and your hand clenches, or (more likely) you panic and squeeze the controller too tightly. https://us.idec.com/idec-us/en/USD/Safety-Components/Enabling-Switches/c/Enabling_Switches https://us.idec.com/idec-us/en/USD/Safety-Components/Enablin...

close04 3y ago

> One thing I learned as amateur EE is to always use just one hand to probe the device under test I was taught to use the back of my hand to avoid gripping the damn thing and never letting go.

renewiltord 3y ago
Same. And I do it like a superstition now.

mauvehaus 3y ago

You're describing the well-known Alanis Morissette technique for electrical work: "I got one hand in my pocket, and the other one holding a DMM"

dmoy 3y ago

> One thing I learned as amateur EE is to always use just one hand to probe the device under test if there is any high voltage or AC involved. I remember in some EE course, the prof randomly stopped in the middle of a lecture and said roughly "Ok now that you all know this theory, I need to remind you that you should not go do your own home electrical work, because you will get ahead of yourself and die from some kind of electric shock" The implication being: 1. You're trained, but for EE not electrician work 2. You'll think you know what to do, even if you don't it'll cloud your judgement 3. As an EE you will make enough to pay a real electrician to do your electrical work Needless to say in the real high power EE courses (t lines, grid, etc), this wasn't even mentioned, because it was just implicitly known that all that stuff was in the realm of "Don't physically touch this stuff in the real world ever because it will kill you and it will hurt the whole time you're dying".

onetimeuse92304 3y ago
I did not mean doing home electrical work. That I do leave to professionals. But there are times I have a device on my bench that is consuming 230V AC. I have a 3kVA separation transformer set up, which makes it safer for me to work with the device (there is no potential between the DUT and the ground). Technically, even without the transformer the residual current protection should kick in and prevent you getting killed between device and the ground. I have tested mine couple of times to check whether it works. But I somehow still feel better with a separation transformer. But there is still the problem that I could touch different parts of the device that are at different potential and then I could get zapped this way. There is not much protection there. Solution -- If you must, don't ever touch more than one place at a time.