4‑Wire DMM Shorting Plug

4-Wire DMM Shorting Plug

4‑Wire DMM Shorting Plug construction project

This was a quick project to con­struct a 4‑Wire short­ing plug for my recent­ly acquired Keithley 2015 bench­top THD Multimeter. The short­ing plug in the pho­to above is the pro­to­type for check­ing dimen­sions, board spac­ing, and oper­a­tion. I designed the board and had it fab­ri­cat­ed by OSH Park. The board dimen­sions are 1.25 x 1.25 inch­es using 1 oz cop­per and an ENIG (immer­sion gold) fin­ish. The posts are spaced on a 0.75″ grid which should work with most 4‑Wire mul­ti­me­ters that use a stan­dard 3/4″ banana plug spacing.
The next step is to order 4 gold plat­ed banana con­nec­tors to reduce the ther­mal EMF (Seebeck Effect), caused by ther­mal dif­fer­ences between con­duc­tors of dis­sim­i­lar materials.

4-Wire DMM shorting plug Top
4‑Wire DMM short­ing plug Top

Boards are shared on OSH Park. 4 Pin Shorting Board V1

2 Replies to “4‑Wire DMM Shorting Plug”

  1. Hello,
    Can you tell me what is the inter­nal diam­e­ter of the via’s?
    I want to order the PCB from OSHPark, but I doubt if I can found cor­rect banana plugs for the PCB. There are banana plugs with M3 or M4 threads.

    Krasimir Kostadinov

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