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 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.