The **2SC4634** (often abbreviated as **C4634**) is a high-speed switching NPN epitaxial silicon transistor primarily designed for high-definition display horizontal deflection output and high-speed switching applications. Below is a detailed breakdown of its specifications and electronic characteristics. --- ### 1. General Specifications | Parameter | Value | | :--- | :--- | | **Polarity** | NPN | | **Package Type** | TO-220ML (Fully isolated) | | **Main Application** | Horizontal Deflection / Switching | | **Material** | Silicon | ### 2. Absolute Maximum Ratings ($T_a = 25^\circ C$) These values represent the extreme limits the component can handle before potential failure. | Symbol | Parameter | Rating | Unit | | :--- | :--- | :--- | :--- | | $V_{CBO}$ | Collector-Base Voltage | 1500 | V | | $V_{CEO}$ | Collector-Emitter Voltage | 600 | V | | $V_{EBO}$ | Emitter-Base Voltage | 5 | V | | $I_C$ | Collector Current (DC) | 5 | A | | $I_{CP}$ | Collector Current (Pulse) | 10 | A | | $P_C$ | Collector Dissipation ($T_c = 25^\circ C$) | 30 | W | | $T_j$ | Junction Temperature | 150 | $^\circ C$ | ### 3. Electrical Characteristics These parameters define how the part behaves in a functional circuit. * **High Voltage Resistance:** Capable of handling up to 1500V, making it suitable for CRT monitors and power supplies where back-EMF or high voltage spikes occur. * **High Speed:** It features low storage time ($t_{stg}$) and fall time ($t_f$), which is critical for efficient power switching. * **Saturation Voltage:** It has a low $V_{CE(sat)}$, meaning it wastes less power as heat when fully "on." ### 4. Typical Applications 1. **Horizontal Deflection Circuits:** Used in high-resolution CRT displays to control the horizontal scanning of the electron beam. 2. **Switch Mode Power Supplies (SMPS):** Acts as the primary switching element in high-voltage DC-DC converters. 3. **Inverters:** Used in specific lighting or industrial inverter circuits requiring high-voltage NPN transistors. --- ### Pin Configuration (Front View) Looking at the labeled side of the TO-220ML package: 1. **Base (B):** Triggering pin. 2. **Collector (C):** Connected to the load. 3. **Emitter (E):** Usually connected to ground.