Looking for small PCB-Hole banana-plug style connector - Page 1
Forum section: electronics / projects

author: BurnedResistor
author_rank: Regular Contributor
timestamp: May 24, 2017, 09:23:32 am
content: Hello All,As part of a project I am including many different test points around the board for ease of debugging. Most of these are used for probing, so I can hold a probe against them or solder a wire to them.However, in this project, there are some which may also be used to introduce a voltage. Normally I might just touch a cable or pogo pin to the connector, but my use cases may require me to connect to 3 or four different pads at the same time. I cant hold that many cables.Therefor, I was wondering if it would be possible to change the smd pads for plated-througholes, and find some kind of connector that I can temporarely push into it.I don't really care about per unit cost of the male connector, as this is a 1 off. I am however not willing to spend more than a few euros per connector. The current is basically 0, everything is logic level and high impedance inputs. Does not have to be very strong as I am only connecting for seconds at a time.Effectively, something similar to what sparkfun did with the staggered PCB header connectors that caused them to pressure fit, but only for one pole at a time!https://www.sparkfun.com/tutorials/114Also, a small footprint is appreciated as there are many of these scattered around!Thanks!

author: tautech
author_rank: Super Contributor
timestamp: May 24, 2017, 09:33:57 am
content: SMD test points are the simplest and can be reused. Grabbers or probes for connections to them.Various styles in the Google images below:https://www.google.co.nz/search?q=smd+test+point&rlz=1C1ASUM_enNZ497NZ497&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwj38IKBnIjUAhUFoJQKHYGtBkYQsAQILw

author: elecman14
author_rank: Unknown
timestamp: May 24, 2017, 11:16:36 am
content: Not sure how well these would "press fit" but they seem like they might work.https://www.digikey.com/product-detail/en/5009/5009K-ND/362671. You might be able to take advantage of the claimed "Snap-fit mounting provides positive retention for wave soldering" from the data sheetAlso a smaller mini grabber that fits through a pth has worked well for me in the past. If you bend the ends to flatten them out they will stay in the holes long enough to make a measurement.

author: ajb
author_rank: Super Contributor
timestamp: May 24, 2017, 12:23:57 pm
content: Is the whole project a one-off, or is the test setup a one-off with multiples of the DUT? If the latter, perhaps a simple bed-of-nails that brings the test points out to connectors of your choice is worthwhile.Otherwise, SMD test loops or elecman14's suggestion with a flattened single-hook test clip and a PTH.

author: ratio
author_rank: Regular Contributor
timestamp: May 24, 2017, 12:32:16 pm
content: Just out of curiosity (this is not my field), would a plated through hole of an appropriate size to accept a banana plug be appropriate? It might not last for continuous usage, but as a test point I'd think it would be just fine. Have I made a poor or unwarranted assumption?

author: BurnedResistor
author_rank: Regular Contributor
timestamp: May 24, 2017, 01:10:26 pm
content: Quote from: ratio on May 24, 2017, 12:32:16 pmHmm. You probably could get contact if you held your tonge at the right angle, but it would only jod if inserted at a specific depth. If pushed in too far, it would not make contact.Would be rather big for a test point tho! Dont know about repeated use!

author: gibbled
author_rank: Regular Contributor
timestamp: May 24, 2017, 09:15:20 pm
content: A small length of brass tubing might work for this application. Can be cut to length with a tubing cutter.

author: Phoenix
author_rank: Frequent Contributor
timestamp: May 25, 2017, 12:46:21 am
content: I wanted something that didn't require any additional PCB parts, but I could connect some wires to carry a decent amount of current (10A) for a short period of testing. As well as a more secure connection when applying 400V. I ended up using 2mm banana plugs - split barrel kind, and 2mm plated holes in the PCB. Maybe too big for your requirements.There are a few different types of banana plugs and sockets:The higher quality one use a bulge in the middle that springs out - I didn't these would connect well to a PTH and would need to be pushed in to just the right position.http://au.element14.com/multicomp/25-206-2/plug-2mm-stackable-black/dp/1699019I opted for the lower quality split barrel type as they can be pushed in any amount - worked fantastically.http://au.element14.com/staubli/22-5071-22-2020-21/plug-2mm-stackable/dp/1085442

author: ratio
author_rank: Regular Contributor
timestamp: May 25, 2017, 02:23:17 am
content: Quote from: Phoenix on May 25, 2017, 12:46:21 amThis is exactly what I was thinking of. I'm glad to know my idea wasn't entirely off.