Karena banyak yang mencari persamaan, pedagang nakal menjual transistor "dijamin original" tapi palsu. Ciri-ciri fisik:

| Parameter | Condition | 2SD998 (NPN) | 2SB778 (PNP) | Unit | | :--- | :--- | :--- | :--- | :--- | | | (V_CB=120V, I_E=0) | max 10 | max -10 | µA | | Emitter Cutoff Current | (V_EB=5V, I_C=0) | max 10 | max -10 | µA | | DC Current Gain (hFE) | (V_CE=4V, I_C=1A) | 50 to 160 | 50 to 160 | - | | Collector-Emitter Saturation Voltage | (I_C=7A, I_B=0.35A) | max 1.0 | max -1.0 | V | | Base-Emitter Voltage | (V_CE=4V, I_C=1A) | typ 1.0 | typ -1.0 | V | | Transition Frequency (fT) | (V_CE=10V, I_C=0.5A) | typ 15 | typ 15 | MHz | | Thermal Resistance | Junction to case | 1.56 | 1.56 | °C/W |