Based on the model number provided, the **FTS-50-R/K** refers to a specific series of **tuning fork crystals** (often associated with manufacturers like Citizen or generic equivalents) commonly used in electronic timing circuits. Below is a breakdown of the electronic components, specifications, and functions of this part. --- ## 1. Component Overview The FTS-50 is a **low-frequency quartz crystal unit**. It is designed as a "Tuning Fork" crystal because its internal structure resembles a tiny tuning fork that vibrates at a specific frequency when an electrical current is applied. | Feature | Specification (Typical) | | :--- | :--- | | **Nominal Frequency** | 32.768 kHz (Standard for RTC) | | **Package Type** | Cylindrical Lead (Through-hole) | | **Dimensions** | Approx. 3.0mm (Diameter) x 8.0mm (Length) | | **Load Capacitance ($C_L$)** | Usually 6pF or 12.5pF | | **Frequency Tolerance** | ±20ppm (Standard) | --- ## 2. Meaning of the Suffix (R/K) In electronic component nomenclature, these suffixes usually denote specific packaging or tolerance variations: * **R:** Often denotes **RoHS Compliance** (Lead-free) or specific Tape & Reel packaging. * **K:** Usually indicates the **Frequency Tolerance** (e.g., ±20ppm) or a specific lead forming style. --- ## 3. Electronic Characteristics To integrate this part into a circuit, engineers look at these primary electrical parameters: ### Frequency: 32.768 kHz This is the most critical aspect. $32,768$ is exactly $2^{15}$. By using a 15-stage binary counter, a circuit can divide this frequency down to exactly **1 pulse per second (1Hz)**, which is the heartbeat of almost all digital clocks. ### Equivalent Series Resistance (ESR) For the FTS-50 series, the ESR is typically around **35kΩ to 50kΩ**. A lower ESR allows the crystal to start oscillating more easily with less power consumption. ### Drive Level These components require very low power, typically around **1.0µW maximum**. Overdriving the crystal (applying too much power) can cause frequency shifts or physical damage to the quartz. --- ## 4. Typical Application Circuit The crystal is almost always used in a **Pierce Oscillator** configuration, which is integrated into most Microcontrollers (MCUs) and Real-Time Clock (RTC) ICs. ```text +-------------------------+ | Microcontroller / RTC | | | | OSC_IN OSC_OUT | +-----+-----------+-------+ | | [C1] [C2] <-- Load Capacitors | | | +-----+-----+ | [GND] ``` * **C1/C2:** Typically 10pF to 22pF capacitors used to match the crystal's rated Load Capacitance ($C_L$). --- ## 5. Summary of Use Cases 1. **Real-Time Clocks (RTC):** Keeping time in computers, servers, and smart meters. 2. **Portable Electronics:** Providing a sleep-mode timer for smartphones and tablets to save battery. 3. **Industrial Timers:** Used in PLC systems for scheduled events.