The **T/R13-R** is an industry-standard designation for a specific type of **Ultrasonic Sensor (Transceiver)**, commonly used for distance measurement, obstacle detection, and proximity sensing. The "T/R" indicates that the component can act as both a **Transmitter** and a **Receiver**. --- ### 1. Key Technical Specifications Below are the typical electronic characteristics found in the T/R13-R series: | Parameter | Typical Value | | :--- | :--- | | **Center Frequency** | 40 kHz (± 1.0 kHz) | | **Sound Pressure Level** | ≥ 110 dB (at 10V / 30cm) | | **Sensitivity** | ≥ -67 dB (at 40kHz, 0dB=1V/ubar) | | **Capacitance** | 2400 pF (± 20%) | | **Directivity** | 60° - 80° (Horizontal/Vertical) | | **Operating Temperature** | -30°C to +80°C | | **Housing Material** | Aluminum or Plastic | --- ### 2. Functional Components The T/R13-R consists of several internal electronic parts that work in harmony: * **Piezoelectric Ceramic Disc:** The "heart" of the sensor. When an AC voltage is applied, it vibrates at its resonant frequency (Transmitter mode). Conversely, when hit by a sound wave, it generates a small voltage (Receiver mode). * **Matching Layer (Acoustic Window):** A thin layer that protects the piezo element and ensures efficient energy transfer between the ceramic and the air. * **Housing/Casing:** Usually 13mm in diameter (hence the "13" in the name), designed to provide structural support and shield against EMI (Electromagnetic Interference). * **Terminals:** Two pins (Anode/Cathode) used to interface with the driving circuit. --- ### 3. Circuit Implementation To use a T/R13-R sensor, you generally need an external circuit consisting of: #### A. Driving Stage (Transmitter) A square wave (usually 40kHz) is generated by a microcontroller or a 555 timer. This signal is often boosted using a transistor or a dedicated MOSFET driver to increase the ultrasonic range. #### B. Receiving Stage (Receiver) The returning "echo" creates a very weak signal (millivolts). This requires: 1. **Preamplifier:** An Op-Amp to boost the signal. 2. **Band-pass Filter:** To remove noise and only allow the 40kHz signal through. 3. **Comparator:** To convert the analog wave into a digital pulse for the microcontroller to calculate "Time of Flight." --- ### 4. Application Examples * **Parking Sensors:** Used in automotive bumpers for reversing assistance. * **Industrial Tank Levels:** Non-contact measurement of liquid levels. * **Robotics:** Obstacle avoidance and SLAM (Simultaneous Localization and Mapping).