The BC547 is a NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to base pin.
The TIP145, TIP146 and TIP147 are 100V 10A 125W Silicon Epitaxial-Base PNP power transistors in monolithic Darlington configuration, mounted in TO-218 Package.
The 2SD882, 2SD-882, 882 is a NPN transistor manufactured by using planar technology resulting in rugged high performance devices. The complementary PNP type is 2SB772.
The device can effectively suppress the surge current, and its resistance and power consumption can be greatly reduced after that through the continuous effect of the current so as not to affect the normal work current. Therefore the Power NTC thermistor