The **FRS-13-R** is a high-performance, ultra-compact **Fast-Response Temperature Sensor** (specifically a platinum resistance thermometer or RTD) designed for precision measurements in liquids and gases. It is commonly used in industrial automation, medical devices, and laboratory equipment where rapid thermal tracking is essential. --- ## Technical Specifications The following table outlines the key electronic and physical characteristics of the FRS-13-R: | Parameter | Specification | | :--- | :--- | | **Sensor Type** | Pt100 (Platinum Resistance) | | **Resistance at 0°C** | 100 $\Omega$ | | **Temperature Range** | -50°C to +200°C | | **Accuracy Class** | Class A / Class B (Standard DIN EN 60751) | | **Response Time ($t_{0.5}$)** | < 0.1 seconds (in water) | | **Material** | Ceramic substrate with thin-film platinum | | **Dimensions** | Approx. 1.3mm x 1.3mm x 0.4mm | --- ## Core Electronic Components ### 1. Thin-Film Element The heart of the FRS-13-R is a **Thin-Film Platinum Layer** deposited onto a high-purity ceramic substrate. This construction allows for: * **High Sensitivity:** Small changes in temperature result in measurable changes in electrical resistance. * **Low Thermal Mass:** Because the part is extremely small, it requires very little energy to change temperature, leading to its "Fast Response" designation. ### 2. Lead Wires The device typically features **AgPd (Silver-Palladium)** or gold-coated wires. These are chosen for: * **Low Parasitic Resistance:** Minimizing error in the 100-ohm circuit. * **Solderability:** Allowing the component to be integrated into larger PCB assemblies or probes. ### 3. Protective Layer The platinum film is covered by a glass or ceramic passivation layer. This protects the delicate electronic circuit from: * Oxidation. * Chemical corrosion. * Mechanical abrasion. --- ## Operating Principle The FRS-13-R operates on the principle of **Positive Temperature Coefficient (PTC)**. As the ambient temperature rises, the vibration of the platinum atoms increases, which impedes the flow of electrons and increases electrical resistance. The relationship is governed by the Callendar-Van Dusen equation: `R_t = R_0 * (1 + A*t + B*t^2)` --- ## Implementation Example To read the FRS-13-R with a microcontroller (like an Arduino or STM32), a **Wheatstone Bridge** or a dedicated RTD-to-Digital converter (like the MAX31865) is used. ```cpp // Example: Basic Resistance to Temp Conversion (Simplified) float calculateTemp(float resistance) { float R0 = 100.0; // Resistance at 0 degrees float alpha = 0.003851; // Standard PT100 coefficient return (resistance - R0) / (R0 * alpha); } ```