The **TCS-4B-R/BL** refers to a specific series of illuminated tactile switches, commonly manufactured by components suppliers like **CIT Relay & Switch**. These components are widely used in control panels, instrumentation, and audio/video equipment. Below is the technical breakdown of its electronic parts and specifications. --- ### 1. Component Identification The model number can be decoded as follows: * **TCS**: Tactile Control Switch series. * **4B**: Designates the physical size and button style (usually a square or rectangular plunger). * **R/BL**: Indicates the dual-LED or specific color configuration (Red/Blue). ### 2. Technical Specifications | Feature | Description | | :--- | :--- | | **Switch Action** | Momentary, SPST (Single Pole Single Throw) | | **Contact Rating** | 50mA @ 12VDC | | **Contact Resistance** | < 100mΩ | | **Operating Force** | Typically 160gf or 260gf (depending on specific sub-model) | | **Travel distance** | 0.25mm ± 0.1mm | | **Operating Life** | ~500,000 to 1,000,000 cycles | --- ### 3. Key Electronic Parts & Materials #### A. The Internal Contact System * **Contact Dome:** Usually made of stainless steel with silver plating. This provides the "tactile" click feel and completes the circuit when pressed. * **Terminals:** Brass or copper alloy with silver or gold plating to ensure high conductivity and prevent oxidation during soldering. #### B. The Illumination System (LEDs) * **Integrated LEDs:** The "R/BL" indicates integrated Light Emitting Diodes (Red and Blue). * **Common Anode/Cathode:** These switches often share a common pin for the LEDs to save space on the PCB. * **LED Voltage:** Typically requires 2.0V for Red and 3.3V for Blue. *Note: External resistors are required to prevent burnout.* #### C. Housing and Actuator * **Base:** High-temperature thermoplastic (LCP or PBT) designed to withstand wave soldering or reflow temperatures. * **Actuator (Plunger):** Polycarbonate (PC), often translucent to allow the LED light to diffuse evenly through the button cap. --- ### 4. Circuit Diagram Representation The switch effectively functions as two separate circuits housed in one body: 1. **The Switch Circuit:** Two pins that close the loop when the button is depressed. 2. **The LED Circuit:** Independent pins (Anode/Cathode) to power the Red and Blue lights. ```text [ Pin 1 ] ----\ ---- [ Pin 2 ] (Switch Contact) [ Pin 3 ] ----(R)---- [ Pin 5 ] (Red LED +/ -) [ Pin 4 ] ----(B)---- [ Pin 5 ] (Blue LED +/ -) ``` ---