Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Solderless Breadboard Problems And Warnings

Status
Not open for further replies.

MrAl

Well-Known Member
Most Helpful Member
Hi,

Measuring the resistance of two wires poked into two connecting holes of a solderless breadboard i can easily measure 10 ohms or even higher. I tried it with clean #24 gauge wires and also the common jumper leads that come in a pack of 20 to 40, made for breadboard projects. The wires themselves, which are so short (less than 6 inches each), measure zero ohms.

This resistance may not be a problem for high input impedance logic, but for analog measurements it really wrecks havoc. 10 ohms with 1ma equals 10mv, which is a large error when using high resolution AD converters. Not only that, but jarring the wires just a little means a different resistance. I measured from 0.5 ohms up to 60 ohms depending on how the wires sit in the hole. The most typical is around 10 ohms though, but it always changes when the board or wires are jarred even just a little.

The measurement is easy: just plug two wires or jumpers into the breadboard and measure the resistance between them with an Ohm Meter. It is very surprising how high the resistance can be. This means if you are working on a project you could see some very strange results using solderless breadboards, and not necessarily at high frequency (where they are known to have problems) but even at DC.

Try the simple measurement and see what you get.
 
Due to oxide around leads or breadboard metals? Cannot we use PCB cleaner or alcohol to clean and fix the breadboard? Or such liquid? (I guess PCB cleaner liquid is also non conductor like alcohol.)
 
Interesting MrAl.

I just tried one of my breadboards.
Using a 0.1uF ceramic capacitor with nice clean and shiny leads as a "test probe", and a fluke bench DMM, I measured 30 to 50 milli Ohms in a random probing session.
In some of the probings there was a hint of intermittency in contact, but nothing obviously worse that about an Ohm or so.

To paraphrase Dirty Harry, "A man has got to know his breadboards limitations"

JimB
 
hi Al,
Just tested 3 of my 6inch * 2.5inch bread boards, about 20 resistance tests, all 0.2R or 0.3R.

It must be the quality of your boards.??

All my b/b's are over 25 years old, never a problem.:)

E
 
Last edited:
MrAl, None of my Breadboards measure more that 0.5 ohms Contact Resistance.
Spraying the few that were a bit high in resistance with "Contact Cleaner" also Reduced that Resistance.

You also need to make sure that Any Wire you plug in are also CLEAN.
Bright and Shiny.
 
I used a solderless breadboard only one time in my entire career and NEVER AGAIN! Intermittent contacts, stray capacitance all over the place and pickup of interference.
 
I Prototype Most of my projects on these Solderless Breadboards. RARELY ANY PROBLEMS.
 
Hello again,

Thanks for the replies and measurements.

I tested some more of mine and found some are sub 1 ohm, like 0.5, but others test to 1.2 ohms or around there.

I took one bottom off and pulled out the little metal mechanism that holds the wire when it is inserted into a hole. It looks like a straight metal channel piece with 5 fingers coming up on both sides. The finger are what grabs the wire and holds it in place.
Even apart i can still stick wires into it, so i stuck two small jumpers into it and measured again. At first i got around 1 ohm, but then if i squeezed it between thumb and forefinger i could make the resistance go down to very low like 0.2 or something like that, maybe 0.1 even. When i let go it goes back up.
I also checked a higher quality board and it basically says that same thing, around 1 ohm maybe 0.5 if i am lucky.

The metal inside doesnt seem strong enough to hold the lead tight enough. There is no visible oxide anywhere and two tests boards are brand new never used.

From what i can see the results are a little too variable, as Audioguru also pointed out. They work for digital gates and stuff but not very well for an application that needs low, consistent resistance.

If you were one of the ones who found low resistance like 0.2 ohms, try moving the lead around a little and see what happens. Keep in mind that you need an ohm meter that can read fast enough to catch any changes. Mine updates about every half second. You can also use a small test current if you like of course.
The ultimate test is on the scope with a current. I would bet that moving the lead a little results in a bunch of noise on the scope. I might try this myself at some point.
Also keep in mind that if the source is high impedance it may not be noticeable because even 10 ohms wont stand up against a 1 megohm input.

Chemlec:
What projects?
 
3M solderless jumpers are 22 AWG, so that gauge is what I also use. My wire is also plated. Have you tried 22 AWG plated wire instead of 24 AWG?

John
 
I use some of those jumper wires with header like pins on the end, They make firm connections to the sockets. I measured about ~.2 ohm with wire zeroed out.

JumperWire-Male-01-L.jpg
 
Hi again,

John:
I use the rounded jumpers too, not just the 24 gauge copper wire. The rounded jumpers are 24 gauge stranded but the ends are solid #22, plated. I get almost the same results. I scrape the copper ends with a razor to make sure they are clean before using, scraping all around the diameter.

Mike:
Those are a little better yes, i'll have to try those next. I was using the rounded end type breadboard jumpers.
 
My Test with a LOW OHM METER.

The PIN's are just Two pieces of 22 AWG Tinned Wire.
And this is the Resistance Between TWO Contact Points.
 

Attachments

  • 0-0-Resistance.JPG
    0-0-Resistance.JPG
    160.3 KB · Views: 216
Another Test on Another OLDER Board.

Don't know Why this one shows Sideways?
 

Attachments

  • 0-0-0-Resistance.JPG
    0-0-0-Resistance.JPG
    163.5 KB · Views: 207
I get about the same too.
When I have had trouble its been hard to find, often the culprit and this might be the same in your case is where I've stuffed a wire in one of the holes that really has been too big for it and relaxed the contact springs, for this reason I dont stick any wires in the holes up to the barrier where ic pins go.
 
From what i can see the results are a little too variable, as Audioguru also pointed out. They work for digital gates and stuff but not very well for an application that needs low, consistent resistance.

hi Al,
This IMHO only applies if you have poor quality version of a bread board.

How 'agu' can claim to post an informed opinion on these boards, having only ever tried it once, beggars belief.
Its most likely his one and only attempt resulted in poor performance due to bad layout.

I Prototype Most of my projects on these Solderless Breadboards. RARELY ANY PROBLEMS.

I get the same results as 'chemelec'.

E
 
Morning Guys

This IMHO only applies if you have poor quality version of a bread board.

EG, would you care to expand on that .. .. .. good quality Breadboard .. .. made by whom ? Obtainable from where ?

A while ago, I spent several sessions trying to get a 3 decade up/down counter using a 4060 IC and a crystal oscillator to function. I could not get it work properly. Being a novice and a bit of a ***** at times, I assumed I was doing something wrong, or I had a wire in the wrong place, or something like that. In the end I dropped kicked the whole thing over my neighbours wall .. .. .. and gave up ! After I'd calmed down, I decided to rebuild the thing on a stripboard with some solder .. .. .. worked first time ! I compared my stripboard circuit with my breadboard circuit - identical ! Conclusion .. .. .. .. ..?? Ye Gods, I heard that from here !! :D

Also IMHO and uneducated opinion, I think the problem is in the principal of the thing .. .. .. you only have to compare the 'stiffness' of the pins of an IC going into an IC socket with that of a piece of tinned wire going into a breadboard hole to recognise the issue is plain to see .. .

I still use breadboards all the time, indeed my solder station is stood on one now to raise it up a little so that I can reach it a little easier !

S
 
Morning S,
I bought my BB's from a UK company named 'Jermyn' many years ago, paid a good price for that time.
A datasheet specification was available for the boards advertised.

Many of today's BB's seem to be from the Far East and of doubtful quality.
From my experience of the complaints I have read, most have occurred only during the past few years with imported BB's

Where did you get your BB's and what did you pay.?

E
 
Hi Eric

I've got some from Rapid Electronics and a couple from Maplins, I'd have to do some research to find the costs, but I don't think they were very expensive - I don't do expensive !

It is a little curious that I also have a BB that came as a freebie with a kit I bought from china .. .. .. that has exactly the same makers marks etc as the Maplin version, but is absolute rubbish .. .. .. if you turn it upside down everything falls out !

Another thing to note is that I am also over 25 years old and have very low resistance ( especially if she's pretty and blonde ) but sadly capacity is waning also :D

Being serious for a minute, I think it's an experience thing .. .. .. which is what I lack .. .. .. I would not prototype a circuit that relies on low capacitance accuracy to work on a breadboard .. .. I've learnt that is asking for problems .. .. however, there is more to life than low capacitance ! .. .. .. .. isn't there ? ... .. .. Oh .. .. ..


S
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top