Where to get multimeter knob contacts? - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: September 07, 2020, 07:15:33 pm
content: You know the contacts on a multimeter knob that brush against the PCB (pictured below)?What are they called? Where can I buy them?Thank you,Bob

author: MosherIV
author_rank: Super Contributor
timestamp: September 07, 2020, 08:21:24 pm
content: They are known as spring contacts.Not sold anywhere that I am aware of.

author: bob91343
author_rank: Super Contributor
timestamp: September 07, 2020, 08:33:36 pm
content: You probably will have to buy or salvage some beryllium copper or phosphor bronze parts of the approximate thickness and cut them to shape.

author: rea5245
author_rank: Frequent Contributor
timestamp: September 07, 2020, 09:29:18 pm
content: Quote from: bob91343 on September 07, 2020, 08:33:36 pmEvery multimeter has them. There must be someone manufacturing them.

author: floobydust
author_rank: Super Contributor
timestamp: September 07, 2020, 10:53:25 pm
content: Those are crap! chinese low purity copper which on gold ENIG pcb I find does not give a decent connection. They have won the race to the bottom for price and quality.Are you looking for replacements or building something using them? If they were leaf/cantilever style, at least silver-plated the quality would be good.

author: rea5245
author_rank: Frequent Contributor
timestamp: September 07, 2020, 11:41:44 pm
content: Quote from: floobydust on September 07, 2020, 10:53:25 pmSo are multimeters experiencing a high failure rate? Or do higher quality multimeters use a different mechanism?I want to build something that uses a multimeter-like rotary switch. But if there's a better alternative, I'd love to hear about it. (My current prototype uses an off-the-shelf rotary switch, but it's more expensive than multimeter rotary switches, and it doesn't have quite as nice a feel to it.)- Bob

author: floobydust
author_rank: Super Contributor
timestamp: September 08, 2020, 05:15:44 am
content: Something about themI have constant problems with oxidationand a poor connection even with DeOxit on them. The copper has a dull look about it. It depends on what signal you are pushing through them.It's a primitive switch contact- any high quality rotary ones have silver or gold plating (Brymen, Agilent, 121GW appear gold coloured). Better Fluke multimeters have their own patented switch mech with I think phosphor or nickel plate and more precise, refined fingers. Fluke started out with an off-the-shelf rotary switch in their earlier handhelds.Some people strip a cheap Harbor Freight $4.99 special and use those, or this guy documented making his own.https://softsolder.com/2012/09/20/multimeter-range-switch-contacts-whoops/If you can make the rest- the knob/ratchet maybe 3D printed it would be neat.They are part of a switch which is part of a multimeter. Switch manufacturers only sell the entire switch. I searched but could not find a specific company offering them, which would save tooling and die cost.

author: janoc
author_rank: Super Contributor
timestamp: September 08, 2020, 09:25:18 am
content: Quote from: rea5245 on September 07, 2020, 09:29:18 pmThey are likely custom parts.