This device is designed as a general−purpose amplifier and switch. The useful dynamic range extends to 60V 200mA 625mW as a switch and to 100MHz as an amplifier.
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 SN74LS83N, SN74HC83N, SN7483 Are high speed 4-bit fuller Adder IC with carry out feature. The IC has four independent stages of full adder circuits in a single package. It is commonly used in applications where arithmetic operations are involved.
The 2SK3515, 2SK-3515, K3515, 3515 is a 450V, 10A, 48W TO-220NIS Package MOSFET, The FUJI Electric manufacturer is a IC Chips with N CHANNEL SILICON POWER MOSFET for more details of 2SK3515 can be seen below.