The part number **FRTD-R-41-K/Q** typically refers to a high-precision **Platinum Resistance Temperature Detector (RTD)** sensor assembly, often utilized in industrial thermal processing and aerospace applications. Below is a detailed breakdown of the electronic and physical characteristics associated with this specification. --- ### 1. Part Number Breakdown (Technical Specifications) While nomenclature can vary slightly by manufacturer (such as IST or Honeywell), the code generally follows this logic: | Segment | Meaning | Technical Detail | | :--- | :--- | :--- | | **FRTD** | Film RTD | Thin-film platinum deposited on a ceramic substrate. | | **R** | Resistance Value | Usually denotes 100 Ohms (Pt100) at 0°C. | | **41** | Physical Size | Often refers to dimensions (e.g., 4.0mm x 1.0mm or 4mm x 1.5mm). | | **K** | Tolerance Class | Class K (or Class B), typically $\pm$ 0.3°C at 0°C. | | **Q** | Lead Configuration | Denotes lead wire material (often Nickel or Silver-coated) or specific termination. | --- ### 2. Core Electronic Components #### A. The Sensing Element (Thin-Film) The heart of the device is a **Thin-Film Platinum resistor**. * **Physics:** It operates on the principle that the electrical resistance of platinum increases linearly with temperature. * **Standard:** Most follow the DIN EN 60751 standard ($a = 0.003851$). #### B. Substrate and Passivation * **Ceramic Base:** Provides high dielectric strength and mechanical stability. * **Glass Layer:** A protective glass coating covers the platinum film to prevent oxidation and mechanical damage. #### C. Leads and Connections * The "K/Q" designation usually points to **automated bonding** of the lead wires. These are designed to be soldered, welded, or crimped into a larger measurement circuit (Bridge circuit or 4-wire Kelvin connection). --- ### 3. Electrical Characteristics | Parameter | Typical Value | | :--- | :--- | | **Nominal Resistance** | 100 $\Omega$ @ 0°C | | **Temperature Range** | -70°C to +500°C (standard) | | **Self-Heating** | 0.4 K/mW at 0°C | | **Response Time** | $t_{0.5} \approx 0.15s$ (in water flow) | | **Measuring Current** | 0.3 to 1.0 mA (to minimize self-heating) | --- ### 4. Comparison: Thin-Film vs. Wire-Wound RTDs | Feature | Thin-Film (FRTD) | Wire-Wound | | :--- | :--- | :--- | | **Vibration Resistance** | High (Solid state) | Low (Wire can break) | | **Size** | Miniature | Bulky | | **Cost** | Low (Mass produced) | High (Manual labor) | | **Stability** | Excellent | Superior (at very high temps) | --- ### 5. Application Circuitry To read the FRTD-R-41-K/Q, it is commonly integrated into a **Wheatstone Bridge** or connected to an **ADC** via a constant current source. ```python # Conceptual calculation for Pt100 Resistance to Temperature def rtd_to_temp(R): R0 = 100.0 alpha = 0.003851 return (R - R0) / (R0 * alpha) # Example: If measured Resistance is 138.5 Ohms # Temperature is approximately 100 degrees Celsius ``` ---