The **2SD1766-R** is a high-performance NPN silicon epitaxial planar transistor. It is primarily designed for use in power amplification and low-speed switching applications. --- ### 1. Key Technical Specifications Below are the absolute maximum ratings and electrical characteristics for the 2SD1766-R: | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | 40 | V | | Collector-Emitter Voltage | $V_{CEO}$ | 32 | V | | Emitter-Base Voltage | $V_{EBO}$ | 5 | V | | Collector Current (DC) | $I_C$ | 2 | A | | Collector Current (Pulse) | $I_{CP}$ | 3 | A | | Collector Power Dissipation | $P_C$ | 0.5 | W | | Junction Temperature | $T_j$ | 150 | °C | ### 2. The "R" Classification The suffix **"R"** refers to the **DC Current Gain ($h_{FE}$)** rank. For this specific part, the gain is categorized as follows: * **Rank R:** $h_{FE}$ range of **180 to 390**. * This indicates high sensitivity, meaning a small base current can control a relatively large collector current. ### 3. Physical Features & Packaging * **Package Type:** Usually comes in the **SOT-89** (Surface Mount Device). * **Size:** It is a miniature package, making it ideal for compact electronic circuits. * **Complementary Part:** The PNP counterpart to this transistor is the **2SB1188**. --- ### 4. Typical Applications The 2SD1766-R is widely used in the following scenarios: 1. **Voltage Regulation:** Used in series regulator circuits due to its stable gain. 2. **Relay Drivers:** Capable of handling up to 2A, making it suitable for driving small relays or motors. 3. **Audio Amplification:** Low-frequency power amplifier stages. 4. **Switching:** Acts as a switch in battery-powered devices. --- ### 5. Pin Configuration (SOT-89) When looking at the front of the device (marked side): 1. **Base (B):** Left Pin 2. **Collector (C):** Middle Pin (and large heat sink tab) 3. **Emitter (E):** Right Pin ```markdown _______ | 1766 | <-- Marking |___R___| | | | 1 2 3 (B)(C)(E) ```