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JST For Dummies

I am interested in learning how to use connectors, but am having trouble finding a beginner's guide. I looked at Molex, but think JST makes more sense for my small projects. Is there a resource that describes what parts are necessary and how to do it. I'm probably only interested in 2, 3 and 4 wire in-line connectors. Is DigiKey the primary source for JST parts? One of the things I want to avoid is buying things that I don't need (e.g., the wrong size crimper). So, as the subject line implies, I'm looking for an absolute beginners' guide to JST connectors.  Thanks.

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I've never seen such a guide. That would be handy indeed. The best place I can point you to is the JST site:


As far as crimpers go I haven't looked beyond the fact that they are pricey compared to buying premade cable assemblies. Digikey isn't they only supplier out there. Personally I've been getting mine from The Orient via eBay. You have to buy a dozen or so but they are priced right.

I've only had to deal with a couple JST connectors in my time but I'll share what I know.

There is the ubiquitous JST RCY connector:

Commonly seen on battery packs. They have a nice 2.5mm pitch that fit onto standard male headers. FWIW I've bought the housings and pins and assembled them with no specific crimping tool, just needlenose pliers.


If you've ever had a Sharp IR sensor you know the JST PH connector:

Does not have a standard 0.1" pitch (I forget what it is). I've seen these used as servo connectors before.


I bought a few micro servos and they came with suprisingly itty bitty JST T-1 connectors:

Super small with 1.25mm pitch. I've only seen them on very small servos.


I went to the JST Web site and am still overwhelmed with options and not understanding what the distinction between them is. I'd love to cut it down to three or four. My understanding (admittedly limited) is that I have to buy male and female connectors and pins in addition to the crimper? I don't mind spending a little money on a crimper (Not the $350+ that I've seen for some of them, but some.) Basically, what I would like is part numbers (presumably from Digikey) for connectors, pins and an inexpensive crimper that will get me started. 2, 3 or 4 line wire-to-wire connectors. Thanks for any advice.

Never seen an inexpensive crimper. Inexpensive is <$200. Searching for "jst crimper" yielded nothing cheap either.

As there are a million part numbers for these kinds of bits 'n pieces I won't go looking for you but I will lead you to the pages that are pertinent. Sometime finding things on digikey is tedious.

JST connector housings

JST connector contacts

Match the contact series to the connector housing series. As far as the differences go it's kind of pick which works best for you. Some have standard pin spacing, some come in smaller packaging, some use different wire gauge ranges, etc, etc. I'm not sure if the smaller ones have a lower current rating than the bigger ones (IIRC the common RCY connectors are rated to 2A). The examples I gave are to illustrate the more common ones I've seen. If you want to have common connectors with other components I'd stick with those series.

Thanks for the links! Narrowing down the bewildering number of options was what I was interested in.

Re: Never seen an inexpensive crimper; I saw this on Sparkfun. $60 is more than I would like to spend, but if it will do the trick, I'll get it. Is there any reason to think that it's a waste of money? Unfortunately, $200 is out of my budget.

you should read through the comments.