How do you use a screwless terminal block?

Question

I know next to nothing about electronics, so treat me accordingly :D

I have these terminal blocks:

To the best of my understanding, wires go in, and the levers clamp down to hold the wires in the place.

1) The levers are really stiff. Am I supposed to be able to flick them with my bare hands?

2) The wires go in the holes on the bottom as seen in the left-hand block, right?

3) Why are there two rows of pins?

4) If I want to connect these blocks together, do I have to pry off that excess plastic piece on the side?

Thanks very much :D

EDIT: Turns out you push down the levers to open the hole, and then they spring back to keep the wire in. The levers are really stiff, but I think they get a little easier to use after pressing them a few times.

The picture is nice, but a datasheet would be much preferred! — Kevin Vermeer, Apr 30 '12 at 19:05
Hmm, the part number is TERMB-000205, but I can't find a datasheet for it. — Wesley May, Apr 30 '12 at 19:14

score 5 · Answer 1 · answered Apr 30 '12 at 19:28

To add to what Leon said, look at the opposite side of the connector to where the pieces of plastic are sticking out. There are probably grooves or slots there intended to mate with the plastic tabs on another connector. This is what is called stackable. You may have to slide two pieces together to get them to end up connected flush with each other. They may pop together, but that is more unusual.

The two pins are not for better electrical connection, but for a better mechanical connection. Solder is a very soft metal, and a single solder joint could be overstressed by the force of pushing on the spring tabs. Two separate pins spreads the force and also descreases torque on the joints. Make the hole in the PCB only a little larger than the pin diameter to minimize the amount of solder between the harder and stronger materials of the pin and the PCB hole. I would make the hole just big enough to guarantee the pin will always fit given the worst case dimensions and PCB hole diameter error.

score 4 · Accepted Answer · answered Apr 30 '12 at 19:17

4

They will probably be even stiffer to operate with the wires in place.

The stripped wire ends go in the holes.

Two sets of pins are provided to make a secure connection to the PCB.

Such connectors are often end-stackable, so you should not have to cut them. If they are not end-stackable, find some that are, or use longer ones.

answered Apr 30 '12 at 19:17

Leon Heller

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A secure connection? So, the wire connects to both of the pins in its column? – Wesley May Apr 30 '12 at 19:20
@Wesley: Yes, probably, but without a datasheet we can't tell for sure. You can of course simply measure between the two pins with a ohmmeter or continuity tester. – Olin Lathrop Apr 30 '12 at 19:29
Yes, it should do. Check it for yourself. – Leon Heller Apr 30 '12 at 19:30

How do you use a screwless terminal block?

2 Answers2