The 2SC3198 is a 60V 150mA 400mW NPN General Purpose Transistor TO-92 Package. This NPN Silicon Epitaxial Planar Transistor for switching and AF amplifier applications.
The 2N7000, 2N-7000, 7000 MOSFET Transistor has a drain voltage of 60V, gate voltage of 40V and a drain current of 200mA in a TO-92 case. A MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor.
The DS1302Z is a trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It communicates with a microprocessor via a simple serial interface IC SOP-8 Pins Package.
The BC548 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.