The **2SB1073-R** is a specific variant of the 2SB1073, which is a PNP epitaxial silicon transistor designed primarily for low-frequency power amplification and high-current switching applications. --- ### 1. General Specifications The 2SB1073-R is known for its high current capacity relative to its compact size. It is often paired with its NPN complement, the **2SD1525**. | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | -30 | V | | Collector-Emitter Voltage | $V_{CEO}$ | -20 | V | | Emitter-Base Voltage | $V_{EBO}$ | -7 | V | | Collector Current (DC) | $I_C$ | -4 | A | | Collector Current (Pulse) | $I_{CP}$ | -7 | A | | Collector Power Dissipation | $P_C$ | 1.0 to 10* | W | *\*Note: Power dissipation depends on the heat sinking and mounting conditions (e.g., 1W without a heatsink, up to 10W with a proper TC=25°C environment).* --- ### 2. The "R" Classification The suffix **"R"** refers to the **hFE (DC Current Gain)** ranking. Transistors are categorized into grades based on their gain levels to ensure circuit stability. | Rank | hFE Range | | :--- | :--- | | Q | 90 to 180 | | **R** | **130 to 260** | | S | 180 to 360 | --- ### 3. Key Features * **Low Saturation Voltage:** $V_{CE(sat)}$ is typically low (around -0.5V at $I_C$ = -2A), which reduces power loss and heat generation during switching. * **High Current Capability:** Capable of handling up to 4A continuously, making it suitable for driving motors or large relay coils. * **Package Type:** Usually found in a **TO-126** or **TO-126MOD** package, which allows for easy mounting to a heatsink. --- ### 4. Typical Applications 1. **Voltage Regulators:** Used in linear power supply circuits. 2. **Motor Drivers:** High current handling allows it to drive small DC motors. 3. **Audio Amplifiers:** Used in the output stage of low-to-medium power audio equipment. 4. **Relay Drivers:** Ideal for switching heavy inductive loads in automation. --- ### 5. Pin Configuration (TO-126) Looking at the labeled side of the transistor: 1. **Emitter (E)** 2. **Collector (C)** 3. **Base (B)** ```markdown _______ | 1073 | | R | |_______| | | | E C B ```