2SD857-Q Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 60 V
• Collector-Base Voltage, max: 60 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 4 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 70 to 150
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The 2SD857-Q transistor can have a current gain of 70 to 150. The gain of the 2SD857 will be in the range from 40 to 250, for the 2SD857-P it will be in the range from 120 to 250, for the 2SD857-R it will be in the range from 40 to 90.Sometimes the "2S" prefix is not marked on the package - the 2SD857-Q might only be marked "D857-Q".The complementary PNP transistor to the 2SD857-Q is the 2SB762-Q.You can replace the 2SD857-Q with the 2N6292, 2N6292G, 2N6293, 2N6473, 2N6474, 2N6487, 2N6487G, 2N6488, 2N6488G, 2SC1826, 2SC1827, 2SC1985, 2SC1986, 2SC2075, 2SC2233, 2SC2334, 2SC2527, 2SC3179, 2SC3253, 2SC3254, 2SC3255, 2SC3258, 2SC3308, 2SC3346, 2SC3540, 2SC3710, 2SC3710A, 2SC3746, 2SC3747, 2SC3748, 2SC3834, 2SC3851, 2SC3851A, 2SC4153, 2SC4511, 2SC4512, 2SC789, 2SD1134, 2SD1265, 2SD1265A, 2SD1267, 2SD1267-Q, 2SD1267A, 2SD1267A-Q, 2SD1269, 2SD1270, 2SD1271, 2SD1274, 2SD1274A, 2SD1274B, 2SD1355, 2SD1356, 2SD1362, 2SD1407, 2SD1407A, 2SD1408, 2SD1411, 2SD1411A, 2SD1568, 2SD1588, 2SD2059, 2SD2060, 2SD363, 2SD389, 2SD389A, 2SD476A, 2SD525, 2SD526, 2SD568, 2SD569, 2SD613, 2SD743, 2SD743A, 2SD812, 2SD823, 2SD857A, 2SD857A-Q, 2SD866, 2SD866A, BD203, BD243A, BD243B, BD243C, BD303, BD535, BD537, BD539A, BD539B, BD539C, BD539D, BD543A, BD543B, BD543C, BD545A, BD545B, BD545C, BD707, BD709, BD711, BD743A, BD743B, BD743C, BD797, BD799, BD801, BD807, BD809, BD907, BD909, BD911, BD949, BD951, BD953, BD955, BDT81, BDT81F, BDT83, BDT83F, BDT85, BDT85F, BDT87, BDT87F, BDT91, BDT91F, BDT93, BDT93F, BDT95, BDT95F, BDX77, D44H11, D44H11FP, D44H8, KSC2334, KSD1408, KSD1588, KSD363, KSD526, KSD568, KSD569, KTC1003, KTC2018, KTC2027, KTC2028, KTD2059, KTD2060, MJE15028, MJE15028G, NTE152, NTE196, TIP41D or TIP42D.