Evaluation of Wireless Wrist Straps
by: ESD Journal Lab

We have been asked many times over the past few years about the
viability of wireless wrist straps. The following is our evaluation of
one wireless wrist strap.
We used a wireless wrist strap that is advertised as:
"It operates using a combination of several physics phenomena like "Ion
Neutralization, Skin Effect, Point Discharge and Corona Discharge
Effect" combined with the principle of differential potential to collect
and dissipate static electricity.
It is a combination of bio-industrial and electronic technologies.
In effect, the wireless wrist strap neutralizes over 80% of the static
electricity on a human body and maintains the potential of a human body
below 150V which is low enough to protect electronic components."
The following is a summary of our evaluation of the strap:
The wrist strap came with a conventional cord for use at the workbench.
However, it is claimed to neutralize the static on a person without the
cord attached "after 15 seconds."
Our tests showed that the wrist strap when connected by it cord had a
resistance from the wearer's hand to ground of 1.3 MegOhms.

Our technician wore insulative shoes (> 10,000 MegOhms) and walked on
an insulative floor.

We charged the technician to 2,000 volts.

When and he walked around with the uncorded wrist strap on, we saw a
decay of the static charge to about 1,000 Volts in 90 seconds.

When and he walked around without the wrist strap, we saw a decay of
the static charge to about 1,000 Volts in 90 seconds.

There was no difference in the time to decay to 1,000 with or without
the wrist strap in place.

With the wrist strap on the walking technician, his potential never
went below 700 volts for over 3 minutes.

We dissected the wrist strap to see what inside would account for the
claimed neutralization. We found only a 1 MegOhm resistor. This supports
our findings that the wireless wrist strap no method for neutralizing a
person not connected to ground by a conventional cord.

It is our opinion that no currently available methods or devices exist
which will effectively ground a person without a tethered cord to ground
or at least a large capacitance.

Sorry! Something that sounds too good to be true probably is.

It is a Hoax....
Paul Signorelli
NARTE Certified ESD Engineer

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