The **7103C** typically refers to a sub-model of the **7000 series sub-miniature toggle switches**, often manufactured by companies like C&K (now part of Littelfuse). These are widely used in instrumentation, telecommunications, and medical equipment due to their reliability and compact size. --- ### 1. Technical Specifications The "7103" prefix identifies the specific circuit configuration and body size, while the "C" suffix usually refers to the terminal type or material. | Feature | Specification (Typical) | | :--- | :--- | | **Circuit Type** | SPDT (Single Pole Double Throw) | | **Switch Function** | ON-OFF-ON (Three positions) | | **Contact Rating** | 5A @ 120V AC or 28V DC; 2A @ 250V AC | | **Electrical Life** | 40,000 make-and-break cycles at full load | | **Contact Resistance** | 10 mΩ max. initial | | **Insulation Resistance** | 1,000 MΩ min. | | **Dielectric Strength** | 1,000 Vrms min. @ sea level | --- ### 2. Circuit Configuration: SPDT (ON-OFF-ON) The 7103 logic allows the switch to control two separate circuits or a single circuit with a neutral "off" position in the center. - **Position 1 (Up):** Connects Pin 2 to Pin 3. - **Position 2 (Center):** All circuits open (OFF). - **Position 3 (Down):** Connects Pin 2 to Pin 1. --- ### 3. Key Components & Materials The construction of the 7103C is designed for durability in industrial environments. * **Actuator:** Usually made of chrome-plated brass. * **Bushing:** Nickel-plated brass with internal O-ring seals available for water resistance. * **Housing:** Glass-filled nylon (UL 94V-0), which is flame retardant. * **Contacts/Terminals:** * **C Terminal:** Often stands for **PC Thru-hole** or specific **Copper Alloy with Silver/Gold plating** depending on the specific manufacturer's catalog code. * **Silver Plating:** Best for power switching. * **Gold Plating:** Best for low-level (dry circuit) switching to prevent oxidation. --- ### 4. Common Applications Due to its "Center Off" feature, the 7103C is commonly found in: * **Motor Control:** Forward/Stop/Reverse operations. * **Audio Equipment:** Selecting between two input sources or muting. * **Test Equipment:** Switching between different measurement ranges or modes. * **Networking:** Manual override switches for servers or routers.