[volt-nuts] Source for spade lugs?
Dr. Frank Stellmach
drfrank.stellmach at freenet.de
Sun Sep 5 17:21:25 UTC 2010
you're right, nowadays it seems difficult to find those low EMF spade
lug cable assemblies.
Even Keithley obviously offers no classical ones any more, i.e. spade
lugs crimped on each side, shielded, etc.
Only special ones for their nV Voltmeters.
Although the crimped version, on (oxygen free) copper stranded wire
offers lowest EMF, I think that this is necessary for ultra low voltage
measurement (nV range) and ultra high precision transfer from a JJ
Ohm measurement can well be handled by Kelvin measurement and EMF
compensation, without usage of low EMF cable.. although a good 4 fold
cable assembly with surrounding shield would be preferred.
I simply use gold plated 4mm banana plugs (SLS4-B = LS 4 + KT-4B, or
LK-4B for complete test leads) from the Swiss manufacturer Multi-Contact.
On my 3458A, these parts deliver EMF well below 1µV after 1-2 minutes
settling time, low contact resistances, and they are mechanically
stable. Even after years of usage they show no wearout of the gold
plating and no relaxation of the elastic force.
They are not suited for higher voltages. By using ordinary HV saftey
cables, EMF plays a minor role only.
See catalogue p.40, p.73:
A pity, they do not offer those spade lugs anymore.
I think that on our metrological (accuracy) level, EMFs firmly around
and below 1µV are sufficient.
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