The **3366-R** typically refers to a high-precision, multi-turn **Trimming Potentiometer** (often part of the 3366 series by manufacturers like Bourns). It is a passive electronic component used to adjust resistance within a circuit for calibration or tuning. ### 1. Key Technical Specifications The "R" suffix often denotes the specific packaging (like Tape & Reel) or a particular terminal orientation. | Feature | Description | | :--- | :--- | | **Component Type** | Cermet Trimming Potentiometer | | **Adjustment Type** | Top Adjust | | **Resistance Range** | Typically 10 $\Omega$ to 2 M$\Omega$ | | **Power Rating** | 0.5 Watts at 70°C | | **Tolerance** | ±10% (Standard) | | **Temperature Coefficient** | ±100 ppm/°C | | **Rotation Life** | ~200 cycles | --- ### 2. Physical Construction The 3366 series is designed for through-hole mounting on Printed Circuit Boards (PCBs). * **Wiper:** A rotating contact that moves along the resistive element. * **Resistive Element:** Made of **Cermet** (Ceramic-Metal composite), providing high stability and low noise. * **Housing:** Usually a square, blue or grey plastic casing that is sealed to withstand wave soldering and board washing. * **Terminals:** Three pins—two ends of the resistor and one center "wiper" pin. --- ### 3. Common Applications Because these are "set and forget" components, they are used in precision environments: 1. **Voltage Division:** Adjusting the output voltage of a power supply circuit. 2. **Sensor Calibration:** Zeroing out offset voltages in operational amplifiers (Op-Amps). 3. **Timing Circuits:** Fine-tuning the RC constant in oscillator circuits. 4. **LCD Contrast:** Controlling the brightness or contrast level of small character displays. --- ### 4. Circuit Symbol and Pinout In a schematic, it is represented by a zig-zag or rectangular resistor symbol with an arrow pointing to the center. ```text Pin 1 (CCW) ----[ Resistor Body ]---- Pin 3 (CW) | Pin 2 (Wiper) ```