JST Connector: How to Choose and Use One?

FACTS CHECKED BY  Jose George​

What advantages do J.S.T. connectors have in the Japanese market and sharply impact the Chinese market? The development in shape and the shell design. The story of connectors is constantly updated, and each country has its successful model. For example, the JST connector uses a metal shell setting, which increases the protection of the connector’s motherboard and extends the connector interface. And then, the multi-form design increases the usage rate. Finally, the waterproof connector is generally higher than other connectors. 

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However, a few other confusions might make you buy the wrong type of connector. Today, we are going to help you make a clear choice.

What are JST Connectors?

Japanese Solderless Terminal, also known as J.S.T., is manufactured by a Japanese company. You can use the JST system to bridge connections and transmit signals for the electrical connection. However, we do not recommend using them in situations where the link will face stresses or strains of any kind. 

Additionally, JST connectors frequently attach to rechargeable battery packs, motors, 3D printers, radio-controlled servos, and circuit boards. Despite its low cost, this connector type is dependable and long-lasting. 

But, in some places, the companies define the JST as a small white connector present on Printed Circuit Boards (P.C.B.)

The Japanese Soldering Terminal or JST retails in many kinds. Thus, you can see the types tagged by series number and features. Also, the JST family caters to the P.C.B.’s need for vertical or horizontal level and the through-hole or surface mount connection.

JST Connector Series

JST connectors are identified mainly by the length between one contact center and the next. There are always more than two contacts in a single line. And some families have multiple rows. This length is the pitch of the connector and determines the connector family. For example, connectors in the family ‘PH’ all have a 2.00mm pitch. 

When identifying the type, you should determine the pitch value first. Next, you need to pay attention to the shape and size of the housing.

Wire-to-board Connectors (Courtesy: https://en.wikipedia.org/)

JST seriesPin-to-pin pitchPin rowsCurrent (Amp)Voltage
(Volt)
Wire size
(A.W.G.)
ShroudLock
VH 3.96mm (0.156 in)11025022 to 16Yes/NoYes
RE 2.54 mm (0.100 in)1225030 to 24NoNo
EH 2.50 mm (0.098 in)1325032 to 22YesNo
XA 2.50 mm (0.098 in)1325030 to 20YesYes
XH 2.50 mm (0.098 in)1325030 to 22YesNo
PA 2.00 mm (0.079 in)1325028 to 22YesYes
PH 2.00 mm (0.079 in)1210032 to 24YesNo
ZH 1.50 mm (0.059 in)115032 to 26YesNo
GH 1.25 mm (0.049 in)115030 to 26YesYes
SH 1.00 mm (0.039 in)115032 to 28YesNo

Wire-to-wire Connectors (Courtesy: https://en.wikipedia.org/)

JST seriesPin-to-pin pitch Pin rowsCurrent
(Amp)
Voltage
(Volt)
Wire size
(A.W.G.)
Features
CY2.50 mm (0.098 in)1325028 to 22Locking
SM 2.50 mm (0.098 in)1325028 to 22Locking, High force

JST Connector Soldering

Most JST through-hole terminals are often unable to resist the hot temperatures you need for the soldering process. Plastic has a lower melting point than the metal used to manufacture them.  

However, specific JST surface-mount connectors can withstand greater temperatures during reflow soldering operations. Thus, you can choose them if the soldering is necessary for your work process.

How do JST Connectors Confuse the Internet?

Connectors are frequently misdescribed by end-users and third-party sellers on multiple websites. Hence, it results in uncertainty about the exact version of a particular connector that is available. Although It is common in forums and web pages to refer to a specific connector by its manufacturer’s name, yet needs to stop using an inaccurate naming convention. Thus, to describe a connector, it is preferable to use the following terminology: 

  • manufacturer’s name,
  • precise connector series, 
  • And optionally the pitch.

It makes the name such as “JST-XH” or “JST-XH-2.50mm” or “2.50mm JST-series” etc.

In addition, you can also use the official JST Co website to confirm the validity and specs of a particular model, which is accessible through a tool.

Crimping a JST Connector

You might see tons of Youtube videos that suggest how to crimp the JST connector. But are they worth your time? Do not crimp the wires on your own. Instead, purchase the pre-crimped wires that are readily available across the market. Since these wires will quickly go into your J.S.T. connector housing, you can create every pairing you want for your system.

Why are we suggesting it? Because the process might get hectic if you are inexperienced in this field. But if you insist on making one, know something first.

What is a good crimp?

Before telling about HOW to achieve a good crimp, let us see what we are trying to do. Since you buy a crimp connector, you will see metal strips across the sides. The machines might press them automatically, but we are trying to push them manually here.

Moreover, there are two sets of wings of metal strips. One branch holds the wire while the other grabs the insulation part.

Hence, after you fix the wires between the extension, you will insert them into the connector housing.

Once you have successfully entered the wire in the case, you will hear a clicking sound. That is your cue that the wire is fixed correctly.

Crimping Tools/Application tooling

Many crimping tools are available online or in physical stores. However, the popular ones are Engineer PA-09 and the original JST-made crimper. However, the original one is on the pricier side. Engineer PA-09 crimps the wire twice, once for the wire and next for the outer insulation, But the J.S.T. crimper does the job in one crimp.

So choose what you think is better for you.

JST Connector Crimping Procedure

Since you have looked into all possible outcomes and information beforehand, let’s dig into the process.

Step 1.            

Start the process by stripping the insulation of your wire. You have to expose around 2 to 3mm of wire.

Step 2.            

Break one crimping connector from its strand and stick it inside the crimping tool. Then, you have to place the wings at the 1.6mm mark of the device. Also, the wings should be facing the inside of the tool to bend back when pressed. Moreover, see that only the inner wings are inside the crimping device. Then, push the crimp connector a little bit inside the tool.

Step 3.            

Now, insert the wire into the crimp connection with your other hand. However, the insulation part should not go inside the crimper. Instead, stick the conducting portion of the wire only. Hold in place and crimp it. You will observe that the outer wings are closed and the inner are still open.

Step 4.            

Next, bend the outside wings and place them on the 1.9mm mark of the tool. Insert the insulation part of the wire and crimp again.

After all these steps, you will be left with a perfectly crimped wire ready for insertion in the connector housing.

Conclusion

J.S.T. connectors are found in many batteries and circuit boards. However, these are not suitable for heavy use, and thus, you might not see them in heavy machinery. Moreover, many experts advise using the pre-crimped wires to fix the J.S.T. connector. Still, if you want to do your own, you might need to be careful about that.

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