The **2SD882-R** (often labeled simply as **D882**) is a popular NPN power transistor designed for medium power applications. It is widely used in voltage regulation, relay drivers, and generic switching circuits due to its high current capacity and low saturation voltage. --- ## 1. Key Specifications The 2SD882 is categorized by its "gain" (hFE). The **-R** suffix specifically denotes a DC current gain range of **60 to 120**. | Parameter | Symbol | Value | | :--- | :--- | :--- | | **Type** | Polar | NPN | | **Collector-Emitter Voltage** | $V_{CEO}$ | 30V | | **Collector-Base Voltage** | $V_{CBO}$ | 40V | | **Emitter-Base Voltage** | $V_{EBO}$ | 6V | | **Continuous Collector Current** | $I_C$ | 3A | | **Peak Collector Current** | $I_{CP}$ | 7A | | **Collector Power Dissipation** | $P_C$ | 1.25W (up to 10W with heatsink) | | **DC Current Gain (R Grade)** | $h_{FE}$ | 60 – 120 | --- ## 2. Pinout Configuration The 2SD882 is typically found in the **TO-126** package (also known as SOT-32). Looking at the flat side with the part number facing you: 1. **Pin 1: Emitter (E)** - Current exits here to the ground or negative rail. 2. **Pin 2: Collector (C)** - Connected to the load. 3. **Pin 3: Base (B)** - The trigger/control pin. --- ## 3. Notable Features * **High Current Handling:** Capable of managing up to 3A, which is high for its compact size. * **Low Saturation Voltage:** $V_{CE(sat)}$ is typically only 0.3V to 0.5V at 2A, meaning it wastes very little power as heat when fully turned on. * **Complementary Pair:** Its PNP counterpart is the **2SB772**, making them ideal for Push-Pull amplifier stages. --- ## 4. Common Applications * **Voltage Regulators:** Used in DC-DC converters and linear power supplies. * **Relay/Solenoid Drivers:** Can easily handle the inductive kickback and current requirements of mechanical relays. * **Audio Amplifiers:** Used in the output stage of low-to-medium power speakers. * **Motor Control:** Suitable for H-bridge circuits for small DC motors. --- ## 5. Circuit Implementation Example A basic switching circuit using a microcontroller (5V) to drive a 12V motor: ```cpp // Schematic Logic: // [MCU Pin] --> [1k Ohm Resistor] --> [Base of D882] // [Collector] --> [Motor Negative Terminal] // [Emitter] --> [GND] // [Motor Positive Terminal] --> [+12V] ``` ---