2SC5171 is a silicon NPN bipolar junction transistor (BJT) — specifically a power transistor designed for amplifier and switching applications. It’s made by Toshiba Semiconductor (and equivalent manufacturers).
📌 Key Characteristics
Type: NPN bipolar junction transistor (BJT)
Package: TO‑220 (through‑hole)
Polarity: NPN
Collector‑Emitter Voltage (VCEO): up to 180 V
Collector Current (IC): up to 2 A
Power Dissipation: ~20 W total, ~2 W at ambient (higher with heatsinking)
Transition Frequency (fT): ~200 MHz (typical)