How would I go about testing an anti-static wrist strap to make sure it works? Someone said to use a continuity tester, but when I tried that with a basic, homemade tester, nothing happened. So I don't know if I didn't do something right or if the strap is defective.
use a "megger" (or other insulation tester)
They're supposed to have a high resistance (1megohm, I think), so they'll dissipate static without flowing tons of current.
Have you googled for it?
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What are you proposing ? Eliminating Dumb Posters ?
A warm human body should show less than 1 megohm at 1.5 volts A typical "Megger" applies 5kv or 10kv to check insulation break-down !
Yukio YANO
Moron! That would destroy the 1 Meg Ohm 1/4 Watt 5% resistor in the wrist strap. Using a' megger' will exceed the breakdown voltage and cause an open spot in the metal film.
There are expensive anti static mat testers that are used to test the surface resistance. BTDT for routine testing of the entire static abatement system for a manufacturing and repair facility. We tested every three months, and replaced any mats that were failing, before they caused problems. There are wrist strap testers, where you clip the ground lead and touch the test pad with your fingers. A 'GOOD' LED lights, if the resistance is in range of the 1 Meg resistor, plus your skin resistance. People with very dry skin have to use a special skin lotion during the day, to meet the specifications. These are used in factories and large service centers, where everyone tests their wrist strap at the start of each shift.
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I don't know where you got your "Megger" from ! But mine applies 500 or
1000 volts to the DUT.
--
Best Regards:
Baron.
Wrong!
A *typical* "Megger" applies either 500V or 1000V depending on model. The source impedance is usually fairly high so that it's practically non-lethal.
More sophisticated insulation testers, such as my Fluke, are switchable from 50V through 1000V.
The correct applied voltage for insulation tests depends on the locally applicable electrical code. I don't know of anywhere where it's more than about twice the supply voltage.
What you are thinking of is an ionization tester, a completely different animal. They do up to about 15kV, but will generally source only microamps.
I have a Hivolt unit, the size of an attache case that goes to 30kV. Now that *is* nasty!
--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)
In the 50's I worked for Westinghouse motor and transformer rebuild. We used a 4000 volt (if I recall) megger to check transformers. One REA transformer about 14 feet tall was rewound and the fellow checking it was standing on a metal barrel with a 1 -1/2 inch wood top. holding the hot insulated lead and reaching to touch the transformer insulator. The lead had been taped up over a bad spot because the supervisor was too cheep to replace it. The voltage found a site to ground through the hand, body, foot board and barrel. Through the fellow to the floor. He did survive but with a burnt hand and foot. To keep the accident quiet he was attending work every day and just sat on a stool until healed so the company would not hear about it. I quit the next week. WW
It has a 1M ohm resistor in it. So just measure between the metal pad under the wrist band and the end of the lead. If it's not approx 1Mohm then it's dead. You can also put it on and measure from the end of the lead to your hand, you should get anywhere from 1Mohm to a few Mohms
Dave.
A basic tester like a light bulb or led will only show contnuity if the resistance of the circuit under test is low enough to let the leb or bulb light up. Your wrist strap has an impedance in the Megohm range, so it will not flow enough current to light an led or incandescent bulb. You would only get microamps and there's no way you would see any glow. Just use a regular digital multimeter on the high resistance range. Use a meter with a high resistance range of at least 2 megohms. Fortunately this includes most meters, even ones that cost less than ten dollars. If you don't have a DMM, get one!
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