Shock delivered through computer headphones?

[Brett Shoelson]

Hi,
I just had the unpleasant experience of getting shocked through a pair of
Sony headphones plugged (via a Radio Shack extension) into the speaker port
of my computer. I wondered if anyone has ever heard of this happening
before? Is this the result of an impedance mismatch in the cables, or might
there be a fault in the headphones or jack? I'm a bit nervous about wearing
these things again.
Thanks,
Brett

 

[Jim Thompson]

On Thu, 22 Jan 2004 14:19:44 -0500, "Brett Shoelson"
<shoelson@helix.nih.gov> wrote:

Hi,
I just had the unpleasant experience of getting shocked through a pair of
Sony headphones plugged (via a Radio Shack extension) into the speaker port
of my computer. I wondered if anyone has ever heard of this happening
before? Is this the result of an impedance mismatch in the cables, or might
there be a fault in the headphones or jack? I'm a bit nervous about wearing
these things again.
Thanks,
Brett

You *should* be nervous. Measure the voltage between the PC case and
earth ground. It should be zero. If not you have a power supply
fault OR a mis-wired AC outlet.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Brett Shoelson]

"Jim Thompson" <thegreatone@example.com> wrote in message
news:f5a010h94ug33i2mvbcsteksjnlfqbg5f3@4ax.com...

On Thu, 22 Jan 2004 14:19:44 -0500, "Brett Shoelson"
shoelson@helix.nih.gov> wrote:

Hi,
I just had the unpleasant experience of getting shocked through a pair of
Sony headphones plugged (via a Radio Shack extension) into the speaker
port
of my computer. I wondered if anyone has ever heard of this happening
before? Is this the result of an impedance mismatch in the cables, or
might
there be a fault in the headphones or jack? I'm a bit nervous about
wearing
these things again.
Thanks,
Brett


You *should* be nervous. Measure the voltage between the PC case and
earth ground. It should be zero. If not you have a power supply
fault OR a mis-wired AC outlet.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Hi Jim,
Thanks for the reply. I cross-posted to sci.electronics.components because I
wasn't sure which was the more appropriate venue for this thread; I got
several responses in that ng, and I'm posting here my reply to that group:
The shock was a quick series of snaps--maybe 3 of them in rapid succession.
Not a continuous jolt...and yes, this is the east coast in January. So I've
added an additional grounding wire to the case of my computer, and ran a
bare copper wire to ground across my desk in front of my keyboard. I'll post
again if I experience (and survive) another one of these.
Regards,
Brett

 

[Richard Crowley]

"Brett Shoelson" wrote ...

Thanks for the reply. I cross-posted to sci.electronics.
components because I wasn't sure which was the more
appropriate venue for this thread; I got several responses
in that ng, and I'm posting here my reply to that group:
The shock was a quick series of snaps--maybe 3 of them
in rapid succession. Not a continuous jolt...and yes, this is
the east coast in January. So I've added an additional grounding
wire to the case of my computer, and ran a bare copper wire
to ground across my desk in front of my keyboard. I'll post
again if I experience (and survive) another one of these.

Likely static electricity. Some power strips have a metal area
where you can touch to discharge yourself (after walking across
the wool carpet!) before touching your computer. Discharging
yourself into the comptuer (or anything connected to it like
mouse, keyboard, etc.) has great potential for permananet damage
to the computer (or any electronic equipment) and should be
actively avoided. Be sure your discharge wire is connected
to the green-wire ground of the power system, and NOT
directly to your computer!