EEVblog #768 - Cordless Anti-Static Wristbands BUSTED!

[EEVblog]

You have to admit though, they are much more comfortable.  O0

Indeed. Productivity should be high!

[senso]

With gigantic anti-static mats that they are always touching is it really necessary for tethered anti-static bracelets?
This is a legit question and not trolling.

[EEVblog]

With gigantic anti-static mats that they are always touching is it really necessary for tethered anti-static bracelets?
This is a legit question and not trolling.

If the setup if done right, then no, you don't need wrist straps.
Ankle straps are quite common for this very reason of the inconvenience of wrist straps.
Proper production facilities have conductive floor with static dissipate tops. Couple that with proper lab coats and clothing, chairs and other stuff and you often don't need a wrist strap.

[Silveruser]

I ordered a couple new straps from Amazon, got a smile when the package arrived.

[chicken]

The cordless anti-static wristband makes a guest appearance in this documentary about Shenzhen: (2:36 and 2:45 mark)
https://youtu.be/8JIvEE9sDdQ

Looks like they are in "professional" use in factories over there.

[Godzil]

It's because in China physic does not work the same as here, the cordless are working there.

[McBryce]

Perhaps the smog is conductive?

McBryce.

[gustavogmb]

Hi everybody, I'm new in this forum.... I have a question... why in these videos they connects the cord to the mat???





and then one of them connect to ground but Dave does not do that? Is that necessary?

cheers


EDIT:


I highly recommend you watch this video, it is very interesting

[drussell]

Ummm...  To actually do anything, your wrist strap or other ESD measures must be grounded.

For safety, if it is connected to a human, you want at least a 1 meg resistor or something to keep you from being quite as likely to fry yourself if you don't know what you're doing.

(Though, actually sometimes I think more people who don't know have no idea what they're doing should probably be darwin-awarded out of existence if they think they know what they're doing, but demonstrably do not, and zap themselves to death... but I digress...)

[McBryce]

Hi everybody, I'm new in this forum.... I have a question... why in these videos they connects the cord to the mat???

and then one of them connect to ground but Dave does not do that? Is that necessary?

cheers

@gustavogmb: To avoid electrostatic discharges (which can damage electronic components) you want everything to be at the same potential, including yourself. So by connecting everything together, you are ensuring that no static discharges can occur. It's important that earth is used because instrumentation such as your oscilloscope is also earthed, so this is the reference point you need to use.

@drussel: I haven't ever heard of someone zapping themselves to death with static electricity, at least not while doing electronics. Unless of course they were hit by lightning while soldering, which wouldn't be dumb, just extremely unlucky

McBryce.

[Brumby]

@drussel: I haven't ever heard of someone zapping themselves to death with static electricity, at least not while doing electronics.

Where was the risk limited to static electricity?  (That is a rather dangerous discussion shortcut, IMO.)

Anyone here with some idea of the 1M resistor knows it is NOT there to protect the wearer from static, but to limit the current should a high risk source - such as mains - gets involved.

[2N3055]

Resistance is there also to prevent sparking that result in extremely fast and high current events.. It is designed to gently dissipate (bleed) static charge and prevent buildup... limiting high currents in mains contact scenario is nice bonus.... win-win

[McBryce]

@drussel: I haven't ever heard of someone zapping themselves to death with static electricity, at least not while doing electronics.

Where was the risk limited to static electricity?  (That is a rather dangerous discussion shortcut, IMO.)

Anyone here with some idea of the 1M resistor knows it is NOT there to protect the wearer from static, but to limit the current should a high risk source - such as mains - gets involved.

The aim of the whole ESD mat / wrist strap setup is to protect against static electricity, not mains current. It may do this as a bonus, but it was definitely not the design intent.

McBryce.

[Brumby]

Irrespective as to whether it was part of the design spec or not - the safety offered by the 1M resistor in a mains exposure scenario is still valid.

That is the point I was making - and, I believe, the one drussell was making.  Nothing to do with design intent (whether that was part of it or not).  A "bonus" if you must, but it is still valid.

[IanMacdonald]

I suppose if you're a punk rocker you could have a wireless wristband with sharp spikes, that would tend to get rid of static by corona discharge. Might result in a few personal injuries though.

I just tend to 'touch down' before handling any sensitive components though. Reckon it's just as effective. The other point to remember is that the static might be on the component rather than on you, so It's important to touch the bag down before taking it out.