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.
The DAC0808LCN is an 8-bit monolithic digital-to-analog converter (DAC), It will interface directly with popular TTL, DTL or CMOS logic levels, and is a direct replacement for the MC1508/MC1408. For higher speed applications.
The ENC28J60-I/SO is a standalone Ethernet controller with an industry standard Serial Peripheral Interface (SPI™). It is designed to serve as an Ethernet network interface for any microcontroller equipped with SPI Communication.
The 2SK2837, 2SK-2837, K2837, 2837 is a 500V 20A N Channel Silicon Field Effect Transistor Or MOFET TO-3PN-3 Package. Chopper Regulator, DC−DC Converter and Motor Drive.