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I think that would be an ohmmeter.
What characteristics do you want to test?
Ken
Yeah, designed to bleed off kV's of static charge at a low rate of current flow. Power is Δ(energy)/Δ(time) and the time is lengthened with a high resistance wrist strap so power goes \/.. . .it's probably in the neighborhood of a megohm.
-------------------------------------------------------------------------------Erick said:Measuring the value of the resistor [470K thru 1M0] and the continuity of the connecting wire will not proof test the strap.
You need to apply a voltage to the strap and the KNOWN ground.
The wrist strap is connected to ground through a coiled retractable cable and 1 megaohm resistor, which allows high-voltage charges to leak through but prevents a shock hazard when working with low-voltage parts. Where higher voltages are present, extra resistance (0.75 megaohm per 250V) is added in the path to ground to protect the wearer from excessive currents; this typically takes the form of a 4 megohm resistor in the coiled cable (or, more usually, a 2 megohm resistor at each end). Very cheap wrist straps do not have conductive fabric and instead use the fabric to hold the metal plate against the skin, which can result in reduced ESD protection over time as the metal corrodes.
hi...
i need an alternate methode for checking the wrist strap.
all time i may not be able to measure the resistance using a DMM.
when i am working i w'll be wearing the strap.without removing the strap
from my hand i want to check the strap.
w'll it be possible by using an oscillatory circuit ?
hi...
In my place around 30-35 wrist straps are there..
in working hours every one w'll use one set.
so checking of these many no's using DMM is difficult.
so i need an alternate method...
hi..
i have all necessary facilities in my lab.
thnx.
hi..hi,
Why didnt you tell us that in the first post, we could have saved ourselves some time.
To test a grounding wrist strap requires a KNOWN good earthing point.
Measuring the value of the resistor [470K thru 1M0] and the continuity of the connecting wire will not proof test the strap.
You need to apply a voltage to the strap and the KNOWN ground.
If I gave some instructions on how to construct a test box, do you have the facilities and expertise to make it.?
hi..hi tnuflora,
I have designed a more useful circuit using a comparator and LED as a 'PASS' indicator.
If you are interested let me know and will prove the circuit on a project board and post the design tomorrow.
OK,hi..
i'm really interested in that.
And i have checked the given ckt. that was really nice.but that is not suitable to use in an industry.
thnx
hi..
i'm really interested in that.
And i have checked the given ckt. that was really nice.but that is not suitable to use in an industry.
thnx