1.5in spacing banana plug to BNC adapter? - Page 1
Forum section: electronics / testgear

author: Smokey
author_rank: Super Contributor
timestamp: August 03, 2014, 09:24:37 pm
content: 0.75in banana to BNC adapters like the below picture are great for things they fit like meters...But... Things like power supplies with floating banana outputs typically have the earth ground terminals in between the floating terminals like in the image below...Well that bumps the spacing of the floating banana outputs to 1.5 inches.Before I get a few PCBs made that have 1.5in spacing banana to BNC I figured I'd ask if there was some place I could get something like that already? I couldn't find anything, but I would think it should exist.

author: David Hess
author_rank: Super Contributor
timestamp: August 03, 2014, 10:22:58 pm
content: Occasionally I have seen well designed test instruments which have three binding posts in an equilateral triangle so a standard 0.75 inch banana plug will fit into any two.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 03, 2014, 10:23:27 pm
content: You can bond -V to GND, if it's okay with your circuit and testing.You really shouldn't be using BNCs there anyway, the current handling is awful. Who supplies DC over coax, anyway?I don't know what all things have 1.5" centers (or three in a row, where you need to use the outer pair, as in this case), so I don't know how appropriate (or not) that actually is.If you're dead set on it, then yeah, might as well make one. Or at least use extension jumpers of some sort (I don't suppose there's such a thing as a 0.75" offset 'S' bend shape?).Tim

author: iRad
author_rank: Regular Contributor
timestamp: August 03, 2014, 10:56:43 pm
content: Have you tried opening the case to see if you can swap the position of the negative and ground terminals. That might be a simpler solution...

author: robrenz
author_rank: Super Contributor
timestamp: August 03, 2014, 11:14:42 pm
content: That is what I did to this supply, switched the posts.Edit; Notice the original - gnd + above the posts

author: Smokey
author_rank: Super Contributor
timestamp: August 03, 2014, 11:24:17 pm
content: Thanks for the responses.I don't really plan on trying to push a lot of current through a BNC.The triangle connector arrangement is a cool concept, but none of the stuff I have has it.I have a few supplies at home and there are a few at work so rewiring the jacks is kind of out.I actually already cooked up a board and placed an order. We'll see how they turned out when they ship here from China.Which brings up the other issue of there not being any cheap v-grove cutters for separating PCBs. I could have technically fit 3 boards in the 5cm x 5cm max board size at Itead. And yes I have a hack saw but that makes ugly board edges. It seems like it should be easy to get a couple cutter wheels and motors and build something up. Another project for the future project list.

author: David Hess
author_rank: Super Contributor
timestamp: August 04, 2014, 02:59:30 am
content: Banana jack to BNC adapters are useful for shielded measurements. I use mine for calibration of some low frequency signal sources like if I want square or sine waves with a very accurate level.I get annoyed with multimeters that put all four of their banana jacks in a line so a plug with 0.75 inch spacing cannot be used between common and the high current jack. The Beckman RMS225 solved this by placing the current jacks in a triangle. Beckman's meter business eventually ended up with Wavetech/Meterman and they have continued that convenient layout on their full size meters which are descendants of the RMS225.

author: Smokey
author_rank: Super Contributor
timestamp: August 04, 2014, 03:20:18 am
content: HA! Look what I just found... $17 USD at onlinecomponents.comhttp://www.pomonaelectronics.com/pdf/d4684_1_01.pdfA little silly lookin, but pretty close.

author: pickle9000
author_rank: Super Contributor
timestamp: August 04, 2014, 03:24:26 am
content: Haven't seen that one before, I kinda like the originality of it.

author: iRad
author_rank: Regular Contributor
timestamp: August 04, 2014, 02:00:22 pm
content: Pomona makes quality stuff, and with a 2.5 inch spread, you have room to spare...

author: iRad
author_rank: Regular Contributor
timestamp: August 04, 2014, 02:08:04 pm
content: This is how some manufactures solve the problem... I have a couple of different Topward supplies, they are very good quality.

author: Smokey
author_rank: Super Contributor
timestamp: August 19, 2014, 05:27:47 am
content: Cool. My boards just came in from Itead. Only took 2 weeks. That's faster than I thought it would be. I haven't even bought parts yet

author: idpromnut
author_rank: Unknown
timestamp: August 19, 2014, 12:32:20 pm
content: Quote from: robrenz on August 03, 2014, 11:14:42 pmNice, except if you want to bind V- to GND

author: robrenz
author_rank: Super Contributor
timestamp: August 19, 2014, 01:19:55 pm
content: That is why I made these in black and red