View 2sd2170 datasheet:

2SD2170 Transistors Medium Power Transistor +20 (Motor, Relay drive) (90 , 2A) -10 2SD2170 Features External dimensions (Units : mm) 1) Built-in zener diode between collector and base. 4.0 2) Zener diode has low dispersion. 1.0 2.5 0.5 3) Strong protection against reverse power surges due to (1) "L" loads. (2) 4) Darlington connection for high DC current gain. (3) (1) Base(Gate) (2) Collector(Drain) 5) Built-in resistor between base and emitter. (3) Emitter(Source) 6) Built-in damper diode. ROHM : MPT3 EIAJ : SC-62 Absolute maximum ratings (Ta=25°C) Parameter Symbol Limits Unit +20 Collector-base voltage VCBO 90 V -10 +20 Collector-emitter voltage VCES 90 V -10 Emitter-base voltage VEBO 6 V 2 A (DC) Collector current IC 3 A (Pulse) *1 Collector po