2SD1681-Q Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 18 V
• Collector-Base Voltage, max: 20 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 1.2 A
• Collector Dissipation: 10 W
• DC Current Gain (h_fe): 70 to 140
• Transition Frequency, min: 150 MHz
• Operating and Storage Junction Temperature Range: -55 to +125 °C
• Package: TO-126

Here is an image showing the pin diagram of this transistor.The 2SD1681-Q transistor can have a current gain of 70 to 140. The gain of the 2SD1681 will be in the range from 70 to 400, for the 2SD1681-R it will be in the range from 100 to 200, for the 2SD1681-S it will be in the range from 140 to 280, for the 2SD1681-T it will be in the range from 200 to 400.Sometimes the "2S" prefix is not marked on the package - the 2SD1681-Q might only be marked "D1681-Q".The complementary PNP transistor to the 2SD1681-Q is the 2SB1141-Q.You can replace the 2SD1681-Q with the 2SC1162, 2SC1368, 2SD439, 2SD793, 2SD882, BD185, KSD882, KSE200, KSH882, KTC2804, KTC2804-O, MJE200, MJE200G or MJE520.