According to historical datasheet information, the 2SC1124 is a general-purpose NPN power transistor designed for low-noise, high-voltage, high-frequency audio output stages. Core Specifications (2SC1124) NPN Silicon Epitaxial Planar Type Package: TO-220 Maximum Collector-Emitter Voltage ( VCEOcap V sub cap C cap E cap O end-sub ): 120V Continuous Collector Current ( ICcap I sub cap C ): 1.5A Power Dissipation ( PDcap P sub cap D ): 2W at (ambient), capable of higher with proper heatsinking DC Current Gain ( hFEh sub cap F cap E end-sub ): Generally categorized into ranges (e.g., 70-240) Complementary PNP Pair: 2SA706 Key Characteristics
The primary electrical parameters defined in the standard C1124 datasheet include: Absolute Maximum Rating VCBOcap V sub cap C cap B cap O end-sub Collector-Emitter Voltage VCEOcap V sub cap C cap E cap O end-sub Emitter-Base Voltage VEBOcap V sub cap E cap B cap O end-sub Continuous Collector Current ICcap I sub cap C Total Power Dissipation ( ) PCcap P sub cap C Maximum Junction Temperature Tjcap T sub j 200∘C200 raised to the composed with power C Transition Frequency fTf sub cap T 120 MHz to 140 MHz Minimum DC Current Gain hFEh sub cap F cap E end-sub Key Technical Advantages of the C1124 High-Voltage Stability With a maximum Collector-Emitter voltage ( VCEOcap V sub cap C cap E cap O end-sub
| Parameter | Value | The Real-World Meaning | | :--- | :--- | :--- | | | 60V | Don't put more than 60V between C and B. Safe for 48V rails. | | Collector-Emitter Voltage (VCEO) | 30V | Critical: This is lower than Vcbo. Do NOT run 60V here. | | Emitter-Base Voltage (VEBO) | 5V | Keep base drive low. | | Collector Current (IC) | 100mA | Low power. Not for drivers or outputs >1W. | | Power Dissipation (Pc) | 2.5W | Use a small heatsink above 1W continuous. | | Gain (hFE) | 40 – 240 | Highly variable by batch. Design for the low end (40). | | Transition Frequency (fT) | 250 MHz (min) | Why it's special: Works well up to ~150 MHz. |
Have a repair story involving a C1124? Let us know in the comments below. And for more vintage transistor guides, check out our library of "better datasheet" replacements. c1124 transistor datasheet better
You don't actually need the original C1124. It is obsolete, expensive, and often counterfeit. Use these "better" alternatives with superior datasheets.
C1815 Transistor Datasheet, Pinout, Equivalent, Voltage, Circuit and Uses
Engineering a "better" circuit around or replacing the C1124 usually stems from three main pain points: | | Collector-Emitter Voltage (VCEO) | 30V |
The 2SC1124 is engineered to balance high breakdown voltages with high-frequency capabilities. Below is the foundational specification set extracted from standard technical datasheets: NPN Bipolar Junction Transistor (BJT) Collector-Base Voltage ( VCBOcap V sub cap C cap B cap O end-sub ): 160V maximum Collector-Emitter Voltage ( VCEOcap V sub cap C cap E cap O end-sub ): 140V maximum Emitter-Base Voltage ( VEBOcap V sub cap E cap B cap O end-sub ): 5V maximum Continuous Collector Current ( ICcap I sub cap C ): 1A maximum Collector Power Dissipation ( PCcap P sub cap C ): 5W (when paired with an adequate heatsink) Transition Frequency ( fTf sub cap T ): 120 MHz to 140 MHz Minimum DC Current Gain ( hFEh sub cap F cap E end-sub ): 50 Physical Package Variations and Pin Configuration
Standard datasheets often gloss over the nuances of the electrical characteristics. Below are the performance metrics evaluated at a standard ambient temperature of 25∘C25 raised to the composed with power C DC Current Gain ( hFEh sub cap F cap E end-sub
If you are trying to match specs, here are the critical parameters: | | Collector Current (IC) | 100mA | Low power
If you are working on a specific repair project, I can help find datasheets or modern, equivalent substitutes for the 2SC1124. Simply share: The specific amplifier or device model Whether you need better power handling or lower noise The PNP counterpart (e.g., 2SA706) Share public link
: Set your digital multimeter to diode mode. Placing the positive probe on the Base terminal (Pin 1) and the negative probe on either the Collector (Pin 2) or Emitter (Pin 3) should register a reliable forward voltage drop between 0.6V and 0.7V . Reversing the probes must show an open loop ( OL ). If you are currently replacing this component, tell me:
| Lead (left to right, flat side facing you) | Function | |---------------------------------------------|----------| | 1 (left) | | | 2 (middle) | Base (B) | | 3 (right) | Emitter (E) |