The C1124 typically comes in a or TO-220 package. When looking at the front of the transistor (labels facing you) with the pins pointing down: Base (B) — Left pin
The 2SC1124 is designed for high-voltage amplification and power driver stages. Note that "C1124" is simply the common shorthand for the full Japanese Industrial Standard (JIS) part number NPN Silicon Max Collector-Emitter Voltage ( cap V sub cap C cap E cap O end-sub 140V to 160V Max Collector Current ( cap I sub cap C 1A (continuous) Power Dissipation ( cap P sub cap C 5W to 7.9W (depending on manufacturer/heatsink) Current Gain ( h sub cap F cap E end-sub Transition Frequency ( f sub cap T 120MHz to 140MHz TO-202 (metal tab) or TO-220 (replacement) Modern Replacements & Equivalents c1124 transistor datasheet better