The **387LS-R1** is a high-precision, low-profile linear position sensor (LVDT - Linear Variable Differential Transformer) primarily used in aerospace and industrial automation. It is designed to convert small physical displacements into electrical signals with extreme accuracy. --- ### 1. Key Technical Specifications The following table outlines the core electronic and physical attributes of the 387LS-R1: | Attribute | Specification | | :--- | :--- | | **Technology** | Linear Variable Differential Transformer (LVDT) | | **Input Voltage** | AC Excitation (typically 3V to 7V RMS) | | **Excitation Frequency** | 400 Hz to 10 kHz | | **Stroke Range** | ± 0.1 inch to ± 0.5 inch (variant dependent) | | **Linearity** | ± 0.25% to ± 0.5% Full Scale | | **Operating Temp** | -55°C to +150°C | | **Termination** | Radial Lead Wires (indicated by "R") | --- ### 2. Internal Components and Functionality The 387LS-R1 operates using electromagnetic induction. It consists of three main internal electronic parts: 1. **Primary Coil:** Located in the center of the housing. When an AC signal is applied, it generates a magnetic field. 2. **Secondary Coils (Pair):** Two coils are wound symmetrically around the primary. They are connected in "series-opposing," meaning their voltages subtract from each other. 3. **Ferromagnetic Core:** A movable rod that slides inside the coils. As the core moves, it changes the magnetic coupling between the primary and secondary coils. #### Signal Logic * **At Null Position:** The core is centered; the voltages in the two secondary coils are equal and opposite, resulting in an output of **0V**. * **Displacement:** As the core moves toward one end, the voltage in that secondary coil increases while the other decreases, creating a net output proportional to the distance moved. --- ### 3. Application Areas The "LS" designation often refers to **Low-Stroke** or **Low-Profile**, making it ideal for tight spaces: * **Aerospace:** Valve position feedback in fly-by-wire systems. * **Actuators:** Monitoring the extension/retraction of hydraulic pistons. * **Testing Equipment:** Dimensional gauging and material deformation testing. --- ### 4. Integration Diagram (Wiring) ```mermaid graph LR A[AC Excitation Source] --> B[Primary Coil] B --> C[Movable Core] C --> D[Secondary Coil 1] C --> E[Secondary Coil 2] D & E --> F[Signal Conditioner/RVDT-to-DC] ```