The **2SB1266-R** is a specific variant of the 2SB1266, which is a PNP epitaxial planar silicon transistor. It is primarily designed for power amplification and high-current switching applications. --- ### 1. Key Technical Specifications The "R" suffix typically refers to the **hFE (DC Current Gain)** ranking, which defines the sensitivity of the transistor. | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | **Collector-Base Voltage** | $V_{CBO}$ | -60 | V | | **Collector-Emitter Voltage** | $V_{CEO}$ | -60 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | -5 | V | | **Collector Current (DC)** | $I_C$ | -3 | A | | **Collector Current (Pulse)** | $I_{CP}$ | -5 | A | | **Collector Power Dissipation** | $P_C$ | 30 ($T_C = 25^\circ C$) | W | | **Junction Temperature** | $T_j$ | 150 | $^\circ C$ | --- ### 2. Gain Classification (The "R" Suffix) Transistors are often binned by their current gain ($h_{FE}$). For the 2SB1266, the classifications are usually: * **Q:** 70 to 140 * **R:** 100 to 200 (The specific part you inquired about) * **S:** 140 to 280 --- ### 3. Physical Characteristics The 2SB1266-R is commonly found in the **TO-220** or **TO-220F** (isolated) package. This package is designed to be bolted to a heatsink to dissipate the heat generated during high-power operation. * **Pin 1:** Base (B) * **Pin 2:** Collector (C) * **Pin 3:** Emitter (E) --- ### 4. Typical Applications Because of its high current handling (3A) and moderate voltage rating, it is used in: 1. **Audio Power Amplifiers:** Used in the output stage or as a driver. 2. **Voltage Regulators:** Functioning as a pass transistor in linear power supplies. 3. **Relay Drivers:** Switching high-current loads from a low-power microcontroller signal. 4. **DC-DC Converters:** Acting as a switching element. --- ### 5. Complementary NPN Pair In push-pull amplifier circuits, the 2SB1266 (PNP) is frequently paired with its NPN counterpart: * **Complementary Part:** **2SD2006** ---