EEVblog Electronics Community Forum

Electronics => Metrology => Topic started by: Overspeed on October 15, 2024, 06:03:39 pm

Title: Zero Ohm connector plates ? an advantage compare to single point ?
Post by: Overspeed on October 15, 2024, 06:03:39 pm
Hello

In NIST 1458 Measurement Service for DC Standard Resistors , they use a triangle zero ohm rather than a single point connection

Does that really provide an gain / improvement as that not complicated to machine from copper plate .

Regards
OS
Title: Re: Zero Ohm connector plates ? an advantage compare to single point ?
Post by: Wazza on October 15, 2024, 07:40:56 pm
The 'advantage' when presenting  zero ohms for a *4 wire* measurement is that the current flow from the stimulus/source terminals does not pass through the meter terminals in any configuration. This reduces possible measurement errors.

Of course thermal emf errors could still be present, depending on the materials used to make the connector plate; but that's another rabbit hole to fall down....

Waz
Title: Re: Zero Ohm connector plates ? an advantage compare to single point ?
Post by: manganin on October 15, 2024, 09:34:48 pm

See section III in the SR1010 manual:

https://www.ietlabs.com/pdf/Manuals/SR-1010_im.pdf (https://www.ietlabs.com/pdf/Manuals/SR-1010_im.pdf)

Title: Re: Zero Ohm connector plates ? an advantage compare to single point ?
Post by: thermistor-guy on October 16, 2024, 12:28:06 am
Quote from: Overspeed on October 15, 2024, 06:03:39 pm
Hello
... they use a triangle zero ohm rather than a single point connection

Also known as a four-terminal junction. It can be circular. See fig. 12 in Riley 1967
Title: Re: Zero Ohm connector plates ? an advantage compare to single point ?
Post by: Overspeed on October 17, 2024, 11:27:20 am
Quote from: Wazza on October 15, 2024, 07:40:56 pm
The 'advantage' when presenting  zero ohms for a *4 wire* measurement is that the current flow from the stimulus/source terminals does not pass through the meter terminals in any configuration. This reduces possible measurement errors.

Of course thermal emf errors could still be present, depending on the materials used to make the connector plate; but that's another rabbit hole to fall down....

Waz

Hello

Thanks for the links

Thermal emf is a concern in design as that mostly impossible to avoid material mix , but try to be close is possible .

Can be interesting to design a mechanical ''frame'' or old style circuit and make tests .

Regards
OS