2SD1666-Q Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 60 V
• Collector-Base Voltage, max: 60 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 3 A
• Collector Dissipation: 25 W
• DC Current Gain (h_fe): 70 to 140
• Transition Frequency, min: 40 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220F

Here is an image showing the pin diagram of this transistor.The 2SD1666-Q transistor can have a current gain of 70 to 140. The gain of the 2SD1666 will be in the range from 70 to 280, for the 2SD1666-R it will be in the range from 100 to 200, for the 2SD1666-S it will be in the range from 140 to 280.Sometimes the "2S" prefix is not marked on the package - the 2SD1666-Q might only be marked "D1666-Q".The complementary PNP transistor to the 2SD1666-Q is the 2SB1133-Q.You can replace the 2SD1666-Q with the 2N6292, 2N6292G, 2N6293, 2N6473, 2N6474, 2N6487, 2N6487G, 2N6488, 2N6488G, 2SC1826, 2SC1827, 2SC1985, 2SC1986, 2SC2075, 2SC2078, 2SC2233, 2SC2334, 2SC2334L, 2SC2527, 2SC3179, 2SC3252, 2SC3252-Q, 2SC3253, 2SC3253-Q, 2SC3254, 2SC3254-Q, 2SC3255, 2SC3255-Q, 2SC3258, 2SC3258-O, 2SC3308, 2SC3308-O, 2SC3346, 2SC3346-O, 2SC3540, 2SC3540-O, 2SC3710, 2SC3710-O, 2SC3710A, 2SC3710A-O, 2SC3746, 2SC3746-Q, 2SC3747, 2SC3747-Q, 2SC3748, 2SC3748-Q, 2SC3834, 2SC3851, 2SC3851A, 2SC4153, 2SC4511, 2SC4511-P, 2SC4512, 2SC4512-P, 2SC789, 2SC789-O, 2SD1134, 2SD1265, 2SD1265A, 2SD1266, 2SD1266-Q, 2SD1266A, 2SD1266A-Q, 2SD1267, 2SD1267-Q, 2SD1267A, 2SD1267A-Q, 2SD1268, 2SD1269, 2SD1270, 2SD1271, 2SD1274, 2SD1274A, 2SD1274B, 2SD1354, 2SD1355, 2SD1355-O, 2SD1356, 2SD1356-O, 2SD1362, 2SD1362-O, 2SD1406, 2SD1407, 2SD1407-O, 2SD1407A, 2SD1407A-O, 2SD1408, 2SD1408-O, 2SD1411, 2SD1411-O, 2SD1411A, 2SD1411A-O, 2SD1568, 2SD1588, 2SD1761, 2SD1913, 2SD2058, 2SD2059, 2SD2059-O, 2SD2060, 2SD2060-O, 2SD2374, 2SD2374-Q, 2SD2374A, 2SD2374A-Q, 2SD313, 2SD362, 2SD362-O, 2SD363, 2SD363-O, 2SD389, 2SD389A, 2SD476A, 2SD525, 2SD525-O, 2SD526, 2SD526-O, 2SD568, 2SD569, 2SD613, 2SD743, 2SD743A, 2SD812, 2SD823, 2SD856, 2SD856-Q, 2SD856A, 2SD856A-Q, 2SD857, 2SD857-Q, 2SD857A, 2SD857A-Q, 2SD866, 2SD866A, 2SD880, BD203, BD241A, BD241B, BD241C, 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, BD935, BD935F, BD937, BD937F, BD939, BD939F, BD941, BD941F, BD949, BD951, BD953, BD955, BDT81, BDT81F, BDT83, BDT83F, BDT85, BDT85F, BDT87, BDT87F, BDT91, BDT91F, BDT93, BDT93F, BDT95, BDT95F, BDX77, D44H11, D44H11FP, D44H8, KSC2334, KSC2334O, KSD1406, KSD1408, KSD1408-O, KSD1588, KSD2058, KSD362, KSD362-O, KSD363, KSD363-O, KSD526, KSD526-O, KSD568, KSD569, KSD880, KTC1003, KTC2018, KTC2018-O, KTC2027, KTC2027-O, KTC2028, KTC2028O, KTD1351, KTD2058, KTD2059, KTD2059O, KTD2060, KTD2060O, MJE15028, MJE15028G, NTE152, NTE196, TIP41D or TIP42D.