The **FTS-73-R/BL** refers to a high-quality, ultra-miniature tact switch (tactile switch) commonly manufactured by components specialists like **Diptronics**. These switches are designed for surface mount technology (SMT) and are widely used in consumer electronics. --- ### 1. Technical Specifications Below are the primary electronic and mechanical characteristics of the FTS-73 series: | Property | Specification | | :--- | :--- | | **Type** | Tactile Switch (Momentary) | | **Mounting Type** | Surface Mount (SMD/SMT) | | **Dimensions** | 3.9mm x 2.9mm (Ultra-miniature) | | **Operating Force** | 160gf or 240gf (Depending on specific sub-type) | | **Current Rating** | 50mA | | **Voltage Rating** | 12V DC | | **Contact Resistance** | 100mΩ Max | | **Life Cycle** | 50,000 to 100,000 cycles | --- ### 2. Key Features and Materials The "R/BL" designation often refers to specific packaging and stem heights or colors. * **Tactile Feedback:** Provides a crisp "click" sensation to the user, confirming that the circuit has been closed. * **Small Footprint:** Its 3.9x2.9mm size makes it ideal for high-density circuit boards where space is at a premium. * **Materials:** * **Base:** High-temperature thermoplastic (LCP) to withstand reflow soldering. * **Contact:** Stainless steel with silver plating for high conductivity and corrosion resistance. * **Terminals:** Brass with silver or gold plating. --- ### 3. Common Applications Due to its reliability and small size, this part is found in: 1. **Wearables:** Smartwatches and fitness trackers. 2. **Portable Electronics:** Bluetooth headsets, digital cameras, and MP3 players. 3. **Communication Devices:** Mobile phones and handheld radios. 4. **Medical Tools:** Portable diagnostic equipment. --- ### 4. Circuit Diagram (Internal) The FTS-73 is a **SPST (Single Pole Single Throw)** normally open switch. ```text (1) o-------o (2) | \ (Push to Close) | (3) o-------o (4) ``` *Note: In most SMT tact switches, pins 1-2 and 3-4 are internally connected.*