The LTC3780 is a DC-DC-Auto-Up & Down-Voltage-Regulator-5-32V-to-1-24V-DC-Adjustable-Converter. My interest in this DC-DC switcher is to operate 19VDC laptops/notebooks and LCD TVs from 12V batteries/solar.
The TIP125, TIP126, TIP127 is a 100V 5A 65W (PNP) Plastic Medium-Power Complementary Silicon Transistors. The devices are manufactured in planar technology with “base island” layout and monolithic Darlington configuration.
IRF3205 is a high-current N-Channel MOSFET that can switch currents up to 110A and 55V. The specialty of the MOSFET is that it has a very low on resistance of only 8.0mΩ making it suitable for switching circuits like Inverters, motor speed control, DC-DC