I am designing a prototyping platform called evive. It is a learning cum prototyping platform for students and makers. Since many times we requires debugging of our circuits, so I thought to include some testing points in PCB. I came across this image: It is used in Dr.Duino (debugging shield). Can anybody explain what it is? Or any other idea about how to give test points in PCB for users, such that user can easily attach the alligator (crocodile) clips or Banana multimeter cable tips.
They are called Test Point Terminals, believe it or not, and here is an example:
Many people make them, in many different colours and shapes.
I have used these on several boards. The ones I generally prefer are the Keystone 5000- and 5100-series. Part number 5000 is a red test point, 5001 is a black test point, 5002 is white, 5003 is orange, 5004 is yellow, 5115 is brown, 5116 is green, etc.
The ones you have are through-hole parts similar to the Keystone 5000 series that Derstrom8 mentions.
You can also get SMT types that take up a lot less space (none on the opposite side) and can be machine assembled.
Despite the simplicity of these parts they are relatively expensive (over $150 US for a reel of 2,000 compared to more like $6 US for 5,000 resistors, reflecting the low demand (most high volume products will use other methods).
While there are plenty of specialized products for small-spaces, just putting holes that are sized for your usual .1" pin header pins works for larger sized board layouts. Probes that can stay in the holes are abundant, or you can solder a pin in and use an alligator clip for that.
Especially for learning/prototyping, the user should have pins laying around anyway, or you can throw some in with the kit.
As everyone says, those are test points, and there are many kinds available. To choose the right type for your needs, and where you need to put them, try to anticipate what you're going to be doing with them. Are you going to clip scope probes to them, or just touch the probe without the clip to them? Do you need to hook the grounding clip of a scope probe to them? Are the test points for important signals within easy reach of a place to hook a scope ground clip?
It seems like none of this makes a difference, but if you take some time to figure this stuff out, they'll be much easier to use. Take it from someone who got it wrong once.