[volt-nuts] Source for spade lugs?

Dr. Frank Stellmach drfrank.stellmach at freenet.de
Sun Sep 5 17:21:25 UTC 2010


  Randy,

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 
standard only.

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:
http://www.multi-contact.com/AcroFiles/Catalogues/TM_Test&Measure_%28de-en-fr%29_hi.pdf

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.

Frank



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