The **FTG-2F-R/Q** is a specific series of high-precision, subminiature thermal flow sensors typically used for gas flow measurement. These sensors operate on the principle of thermal anemometry and are designed for integration into medical devices, industrial automation, and environmental monitoring systems. --- ### 1. Core Technical Specifications The "R/Q" designation usually refers to specific variations in flow range or output signal characteristics. | Feature | Specification (Typical) | | :--- | :--- | | **Measurement Principle** | Thermal Mass Flow (MEMS Chip) | | **Flow Range** | 0 to 200 sccm / 0 to 1000 sccm (Variant dependent) | | **Accuracy** | ±3% to ±5% of Reading | | **Operating Voltage** | 5V DC (Stabilized) | | **Output Signal** | Analog (0.5V to 4.5V) or Digital (I2C) | | **Response Time** | < 10ms | --- ### 2. Electronic Components & Internal Architecture The FTG-2F-R/Q series utilizes a **MEMS (Micro-Electro-Mechanical Systems)** architecture. The internal electronic structure consists of: * **Micro-Heater:** A platinum or polysilicon resistor located at the center of a thin dielectric membrane. It creates a local heat field. * **Thermostacks (Thermopiles):** Two sets of temperature sensors located symmetrically upstream and downstream of the heater. * **Signal Conditioning ASIC:** An internal Integrated Circuit that performs: * **Amplification:** Boosting the micro-volt signals from the thermopiles. * **Linearization:** Converting the non-linear thermal output into a linear voltage or digital flow value. * **Temperature Compensation:** Correcting for changes in ambient gas temperature to maintain accuracy. --- ### 3. Pin Configuration and Interface The physical interface typically uses a 4-pin or 5-pin connector. | Pin Number | Function | Description | | :--- | :--- | :--- | | **1** | VCC | Power Supply (+5V) | | **2** | GND | Ground | | **3** | OUT/SDA | Analog Output Voltage or I2C Data | | **4** | SCL | I2C Clock (for digital variants) | --- ### 4. Operating Principle (Thermal Mass Flow) 1. The electronic circuit provides a constant current to the **Micro-Heater**. 2. When gas is stationary, the heat distribution is symmetrical across the sensors. 3. As gas flows (from **R** to **Q** or vice versa), it carries heat away from the upstream sensor and toward the downstream sensor. 4. The temperature differential ($\Delta T$) is measured by the electronic bridge circuit. 5. The ASIC converts this $\Delta T$ into a standardized electrical signal proportional to the **Mass Flow Rate**. --- ### 5. Application Circuit Example To interface this part with a microcontroller (like an Arduino or ESP32), a simple RC filter is often recommended on the output line to reduce noise. ```cpp // Basic Arduino snippet to read the Analog output of FTG-2F const int flowPin = A0; void setup() { Serial.begin(9600); } void loop() { int rawValue = analogRead(flowPin); float voltage = rawValue * (5.0 / 1023.0); // Mapping voltage to flow (Reference datasheet for exact curve) float flowRate = (voltage - 0.5) * 250; // Example mapping Serial.print("Flow: "); Serial.println(flowRate); delay(100); } ```