Design Con 2015
Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 8 / 10   >   >>
Wnderer
User Rank
CEO
Re: power strip and ground plug adapter
Wnderer   8/13/2014 7:46:03 PM
NO RATINGS
@David Ashton Great little gadget, much easier than my idea if you can get them easily.


Digikey has them.

 

 

David Ashton
User Rank
Blogger
Re: power strip and ground plug adapter
David Ashton   8/13/2014 6:17:14 PM
NO RATINGS
@Wnderer....sorry, only noticed this post after I posted mine above.  Great little gadget, much easier than my idea if you can get them easily.

David Ashton
User Rank
Blogger
Re: Maybe...
David Ashton   8/13/2014 6:14:31 PM
NO RATINGS
@Max...sorry to rain on your parade (or pee on your fire) but I would say 100% of all the brick type laptop and other power supplies I have ever taken apart (and there have been a few) have been switching types with the output isolated from the mains.

A mini-tower desktop computer might be different - those power supplies usually have a connection between the mains earth and the case of the PC....but I am not sure whether this will extend to the USB shield, I will check mine when I can.

Your solution might be to just switch your power supply off rather than unplugging it.  Of course you should also check if the power supply ground goes all the way through to the output.

The best solution would be to get a mains cable with a proper 3-pin plug,  cut the IEC end off (preferably while it is NOT plugged in :-), strip it back a bit, and cut off and insulate the white and black wires (which is what I think you have in the US) leaving the green earth wire only - and connect that to your anti-static mat.  This does assume you have a spare power outlet where you are working, and that G the G does not want to use said outlet while you are electronicking...

PS to avoid the white and black wires shorting, cut them off different lengths.  Then get some pliers and pull the insulation so you don't have wire ends sticking out.  Then insulate them with tape.   As the Irish would say....To be sure...to be sure...

Max The Magnificent
User Rank
Blogger
Re: Braided shield
Max The Magnificent   8/13/2014 5:41:37 PM
NO RATINGS
@MeasurementBlues: Congratulations Max, you've just created a pigtail, a wonderful source of radiated emissions.

Thank-you-very-much ... I'll be playing here all week :-)

MeasurementBlues
User Rank
Blogger
Google has found you
MeasurementBlues   8/13/2014 5:36:17 PM
NO RATINGS
@Max, I get a Google alert for "electrostatic discharge" and you've been picked up.

MeasurementBlues
User Rank
Blogger
Braided shield
MeasurementBlues   8/13/2014 5:30:59 PM
NO RATINGS
Congratulations Max, you've just created a pigtail, a wonderful source of radiated emissions.

I'll be posting an article to my EDN blog about how those pigtails are evil.

The braided shielding -- shown pulled back from the inner wires, twisted together, and sticking out of the right-hand side



MeasurementBlues
User Rank
Blogger
Re: Wear the wristband
MeasurementBlues   8/13/2014 5:26:26 PM
NO RATINGS
As you surely know, never ever float the scope.

zeeglen
User Rank
Blogger
Re: Wear the wristband
zeeglen   8/13/2014 5:24:09 PM
NO RATINGS
@Martin So if your circuit is floating and you're connected to the low side of its power supply, you should be OK.

Also a good idea to connect a scope probe ground to a floating circuit as the first connection so that the circuit is no longer floating.  I've zapped MOSFETs by connecting the probe tip to the gate first before the ground.

MeasurementBlues
User Rank
Blogger
Wear the wristband
MeasurementBlues   8/13/2014 5:13:00 PM
NO RATINGS
@Max,

The purpose of the wrist band is to provide ahigh-resistance (leakage path) from you to whatever you're working on. So if your circuit is floating and you're connected to the low side of its power supply, you should be OK. If the power supplye is indeed connected to the ground lead of the AC mains, then that's better.

Some years ago, I was installing a new hard drive in my desktop PC. When I powered it up, the power sypply fan came on, but nothing else. I had zapped the motherboard and needed a new one. Since that day, I always wear an ESD wrist strap.

ESD wrist straps whould be part of everyone's EMC troublshooting kit.

MeasurementBlues
User Rank
Blogger
What ground is actually good for.
MeasurementBlues   8/13/2014 5:01:27 PM
NO RATINGS


<<   <   Page 8 / 10   >   >>


Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Analog Faceplate Design Decisions: Art or Science?
Max Maxfield
48 comments
My degree is in Control Engineering -- a core of math with "surrounding subjects" of electronics, mechanics, and hydraulics and fluidics. The only official programming I did as part of ...

Jolt Judges and Andrew Binstock

Jolt Awards: The Best Books
Jolt Judges and Andrew Binstock
1 Comment
As we do every year, Dr. Dobb's recognizes the best books of the last 12 months via the Jolt Awards -- our cycle of product awards given out every two months in each of six categories. No ...

Engineering Investigations

Air Conditioner Falls From Window, Still Works
Engineering Investigations
3 comments
It's autumn in New England. The leaves are turning to red, orange, and gold, my roses are in their second bloom, and it's time to remove the air conditioner from the window. On September ...

David Blaza

The Other Tesla
David Blaza
5 comments
I find myself going to Kickstarter and Indiegogo on a regular basis these days because they have become real innovation marketplaces. As far as I'm concerned, this is where a lot of cool ...