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Max The Magnificent
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Re: Laptop grounded?
Max The Magnificent   8/29/2014 9:43:37 AM
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@zeeglen: When breadboarding it can help to do all your work on a new cookie baking sheet.  The raised edges keep small parts contained within your work area, and since your wrists can rest on the raised edges everything is at the same potential as the worker.

This is really good advice -- especially for younger people -- I have a young lad in mind (a friend's grandson) who is just starting to play with the Arduino -- his family doesn't have much money, so splashing out on earth straps and pads and those banana-to-power adapters would be out of his range -- also teaching him the discipline to use them correctly would be problamatic -- but the cookie sheet idea woudl be perfect for him -- I'll tell him when I see him next week. 

Sanjib.A
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CEO
Re: power strip and ground plug adapter
Sanjib.A   8/24/2014 9:26:38 AM
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Wow!! This is a cool little gadget!! Really appreciate the idea!! The only remaining thing is then to check if the ground point of the socket is "really" connected to ground.

zeeglen
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Re: Maybe...
zeeglen   8/21/2014 10:30:38 PM
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@Max I can so imagine this scene...

Well, the boss was not around and I don't know if he ever found out.  We were in the habit of touching the rack metalwork before touching boards, but my colleague forgot this one time.

zeeglen
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Re: Laptop grounded?
zeeglen   8/21/2014 5:27:10 PM
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@JLBrake you can use equipotential bonding.

When breadboarding it can help to do all your work on a new cookie baking sheet.  The raised edges keep small parts contained within your work area, and since your wrists can rest on the raised edges everything is at the same potential as the worker.  Just be sure to touch the cookie sheet first when starting a session, and maintain contact with the cookie sheet.

Max The Magnificent
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Re: Maybe...
Max The Magnificent   8/21/2014 5:15:56 PM
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@zeeglen: "It's not very hot."  Then a few seconds later "But it sure is getting hot now!"

I can so imagine this scene...

Max The Magnificent
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Re: Laptop grounded?
Max The Magnificent   8/21/2014 5:14:31 PM
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@JLBrake: Based on this post we are going to make some samples of a USB to banana jack adaptor to see how this would work.  The adaptor will allow a standard wrist strap to be connected to the USB.

You might want to make it a double-banana jack -- that way someone could connect both their wriststrap and their anti-static mat to the same USB plug

Max The Magnificent
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Re: Laptop grounded?
Max The Magnificent   8/21/2014 5:12:58 PM
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@JLBrake: ...If grounding to the electrical ground is not possible, you can use equipotential bonding....

WONDERFUL point -- I'm kicking myself for not thinking about this.

zeeglen
User Rank
Blogger
Re: Maybe...
zeeglen   8/21/2014 4:34:29 PM
@studleylee I still keep a A/D converter I bought from Analog Devices that cost me $100 in 1984. I zapped it.

An engineering lab actually had a carpeted floor.  Was supposed to be anti-ESD carpet, but the installer got it wrong, and it had to be sprayed weekly with some kind of chemical.  Back then we did not have heel straps or wrist straps.

Anyway, on a cold dry winter day in the Great White North, a colleague had just installed the 1st of 10 samples of his brand new ASIC into the socket.  It was in a ceramic package with a metal top. We fired the board up, then we wondered how warm the ASIC was running.  My friend reached out to feel it - I said "Static!" but it was too late.  We could hear the 'snap' of a strong ESD discharge.

He said "It's not very hot."  Then a few seconds later "But it sure is getting hot now!"

One down, nine to go.

studleylee
User Rank
Manager
Re: Maybe...
studleylee   8/21/2014 4:13:53 PM
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You just put it into a known state.....

I still keep a A/D converter I bought from Analog Devices that cost me $100 in 1984. I zapped it. Now it's a reminder. -Lee

JLBrake
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Rookie
Re: Laptop grounded?
JLBrake   8/21/2014 3:44:31 PM
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There's lots of stuff going here, but let me try to clarify some things.

 When working on the something like a laptop, there are really two options of grounding for ESD purposes.  

1.  Ground all conductors and dissipative materials (people, product, worksurface, etc) through an electrical ground (third wire).  This is the preferred method for electronics manufactures because the electrical ground is where other equipment (soldering iron, scopes, etc) used in the production environment if grounded, but not always available in "field" applications. 

2. If grounding to the electrical ground is not possible, you can use equipotential bonding. Equipotential bonding connects all conductors and dissipative materials in the environment together.  If you are working on something such as a laptop, you would use an alligator clip to connect the wrist strap to the housing of the laptop. 

Both methods essentially do the same thing in creating an equipotential balance between all items and personnel.  ESD events can only occur when there is a difference in the potential. Note that only conductors and dissipative materials can be grounded, insulators require ionization to control ESD. 

Based on this post we are going to make some samples of a USB to banana jack adaptor to see how this would work.  The adaptor will allow a standard wrist strap to be connected to the USB.

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