## Technical Overview: 2SA497-R Transistor The **2SA497-R** is a classic Silicon PNP epitaxial transistor primarily designed for high-frequency amplification and high-speed switching applications. It was commonly manufactured by Toshiba and is often paired with its NPN complement, the **2SC497**. --- ### 1. Key Technical Specifications The "R" suffix typically denotes a specific **hFE (DC Current Gain)** classification range. | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | -35 | V | | Collector-Emitter Voltage | $V_{CEO}$ | -30 | V | | Emitter-Base Voltage | $V_{EBO}$ | -5 | V | | Collector Current (DC) | $I_C$ | -500 | mA | | Collector Power Dissipation | $P_C$ | 600 | mW | | Junction Temperature | $T_j$ | 150 | °C | | DC Current Gain (R classification) | $h_{FE}$ | 40 – 80 | - | --- ### 2. Pin Configuration The 2SA497 usually comes in a **TO-39** metal can package, which provides better heat dissipation compared to plastic TO-92 packages. 1. **Emitter**: (Connected to the case in some variants, or identified by a tab) 2. **Base**: Input signal control 3. **Collector**: Output --- ### 3. Common Applications Due to its robust metal packaging and frequency response, it is found in: * **Audio Amplifiers**: Used in driver stages for low-to-medium power audio. * **Switching Circuits**: Handling loads up to 500mA. * **RF Stages**: High-frequency signal processing in older radio equipment. --- ### 4. Modern Equivalents / Replacements If the 2SA497-R is unavailable, the following transistors are often used as substitutes, though pinout and package (TO-92 vs TO-39) may differ: * **2SA708** (Similar voltage/current) * **BC327** (General purpose PNP, different package) * **2SA1013** (Higher voltage handling) --- ### 5. Identifying the "R" Classification In Japanese industrial standards (JIS), transistors are often binned by gain: * **O (Orange)**: 70 – 140 * **Y (Yellow)**: 120 – 240 * **R (Red)**: 40 – 80 (As seen in the 2SA497-R)