The **FUD-44-R/Q** is a high-performance infrared (PIR) motion sensor module typically used in security systems, lighting control, and automated occupancy detection. It is designed to detect the thermal radiation emitted by moving objects (specifically humans). --- ### 1. Key Technical Specifications Below are the primary electronic characteristics of the FUD-44-R/Q: | Parameter | Specification | | :--- | :--- | | **Sensor Type** | Passive Infrared (PIR) | | **Element Configuration** | Quad Element (4 sensing zones) | | **Operating Voltage** | 3V - 15V DC (typical) | | **Output Type** | Analog / Pulse (Digital conversion via external IC) | | **Field of View** | 120° Horizontal / 90° Vertical (with lens) | | **Spectral Response** | 5μm to 14μm | --- ### 2. Core Electronic Components The device consists of several critical layers that allow it to function as a motion detector: #### A. Pyroelectric Ceramic Element The heart of the FUD-44-R/Q is a ceramic material that generates an electric charge when exposed to infrared radiation (heat). The "Quad" design means it has four separate sensing areas, which significantly reduces false alarms caused by pets or environmental changes. #### B. Infrared Window (Optical Filter) A specialized silicon-based window covers the sensor. This acts as a band-pass filter, allowing only the infrared wavelengths emitted by the human body (approx. 8–14 microns) to pass through while blocking visible light and ultraviolet rays. #### C. Field Effect Transistor (FET) Inside the metal housing (TO-5 package), there is a built-in FET. Since the charge generated by the ceramic element is extremely high impedance and low current, the FET acts as an **Impedance Converter**, allowing the signal to be processed by external operational amplifiers. --- ### 3. Connection Pinout The sensor typically features a standard 3-pin configuration: 1. **VDD (Drain):** The supply voltage input. 2. **OUT (Source):** The signal output pin. This requires a source resistor to ground to convert current fluctuations into voltage. 3. **GND (Ground):** The common return path connected to the metal casing for shielding. --- ### 4. Application Circuitry Requirement The FUD-44-R/Q is a **transducer**, not a complete system. To use it in a project, you generally need: * **Fresnel Lens:** To concentrate infrared energy onto the sensor. * **Amplifier Stage:** To boost the micro-volt signals to a readable level. * **Window Comparator:** To determine if the signal has crossed a specific "motion threshold." ---