The **JST 3JS 2.5-R** refers to a specific series of wire-to-board connectors manufactured by JST (Japan Solderless Terminals). These are widely used in consumer electronics, automotive modules, and power supply units due to their reliable locking mechanisms and compact pitch. --- ## Technical Specifications The "2.5" in the name denotes the **pitch** (the distance between the centers of two adjacent pins), which is **2.5mm**. | Parameter | Specification | | :--- | :--- | | **Pitch** | 2.5 mm | | **Current Rating** | 3A AC/DC (AWG #22) | | **Voltage Rating** | 250V AC/DC | | **Temperature Range** | -25°C to +85°C | | **Contact Resistance** | 10mΩ Max (Initial) | | **Insulation Resistance** | 1,000MΩ Min | | **Applicable Wire** | AWG #28 to #22 | --- ## Key Components of the 3JS 2.5-R System ### 1. The Housing (Plastic Shell) The housing is the female part that holds the crimped terminals. * **Material:** Usually Nylon 66 (UL94V-0). * **Design:** Features a friction lock or a side-lock mechanism to prevent accidental disconnection caused by vibration. ### 2. The Contacts (Crimp Terminals) These are the metal pieces crimped onto the wires and inserted into the housing. * **Material:** Phosphor bronze or Brass. * **Plating:** Usually Tin-plated to prevent oxidation and ensure high conductivity. ### 3. The Headers (PCB Mount) These are the male pins soldered directly onto the Printed Circuit Board (PCB). * **Top Entry:** The connector plugs in vertically (from the top). * **Side Entry:** The connector plugs in horizontally (from the side). --- ## Features and Applications ### Features * **Polarized Design:** The shape of the housing prevents the connector from being inserted upside down. * **High Pressure Contact:** The terminal design ensures a high-pressure connection point, reducing the risk of signal loss. * **Secure Locking:** The "R" variant often indicates a specific locking style or a revision intended for high-reliability environments. ### Common Applications * **Computer Peripherals:** Internal cooling fan headers or LED strips. * **Household Appliances:** Control boards for washing machines or air conditioners. * **Industrial Equipment:** Signal transmission between sensors and main logic boards. --- ## Pinout Example (3-Pin Configuration) While pinouts depend on the specific circuit design, the physical layout for a 3-pin JST 2.5mm connector is typically: ```text [ Pin 1 ] --- [ Pin 2 ] --- [ Pin 3 ] (VCC) (Signal) (GND) ```