The **9B-R** designation typically refers to a specific series of **Quartz Crystals** manufactured by **TXC Corporation**. These are passive components used to provide a precise clock frequency for microcontrollers, wireless modules, and other digital circuits. --- ## 1. Component Overview: 9B Series The "9B" series represents a standard **HC-49/S** package. This is a "Low Profile" version of the classic metal-can through-hole crystal. ### Technical Specifications | Feature | Specification (Typical) | | :--- | :--- | | **Package Type** | HC-49/S (Through-Hole) | | **Frequency Range** | 3.2 MHz to 90 MHz | | **Frequency Tolerance** | ±30 ppm (Standard) | | **Operating Temperature** | -20°C to +70°C (Standard) | | **Load Capacitance** | 12pF, 18pF, 20pF, or Series | | **Shunt Capacitance ($C_0$)** | 7 pF Max | --- ## 2. Deciphering the Part Number (9B-R) While the full part number is usually longer (e.g., `9B-12.000MAAJ-B`), the "R" suffix or inclusion often refers to specific compliance or packaging: * **9B:** The series code (HC-49/S Metal Can). * **-R:** Often signifies **RoHS Compliance** (Lead-free) or **Taping/Reel** packaging depending on the specific distributor's internal coding. --- ## 3. Key Applications Because of its size and stability, the 9B-R crystal is found in: 1. **Microprocessor Clocks:** Providing the heartbeat for CPUs. 2. **Communication Gear:** Used in ZigBee, Bluetooth, and Wi-Fi modules for frequency reference. 3. **Consumer Electronics:** Found in TVs, white goods (fridges/washing machines), and PC motherboards. 4. **Automotive:** Infotainment systems and basic control modules. --- ## 4. Circuit Implementation When using a 9B series crystal, it is typically paired with two load capacitors ($C_1$ and $C_2$) to create an oscillation circuit. ```cpp // Example of how a crystal frequency is defined in firmware (C++) #define F_CPU 16000000UL // Defining a 16MHz 9B Crystal for timing ``` ### Typical Schematic Connection: * **Pin 1:** Connected to XTAL_IN of MCU. * **Pin 2:** Connected to XTAL_OUT of MCU. * **Capacitors:** Both pins are bypassed to Ground via 12pF-22pF capacitors. ---