The PIC microcontroller is a single-chip computer with RAM, ROM, I/O ports and a CPU. The PIC16F73 has features like a RISC CPU, 4K bytes of flash memory, 192 bytes of RAM, three I/O ports and a built-in oscillator. It has peripherals like timers, PWM, ADC and serial communication modules. The PIC memory is divided into program memory for instructions and data memory consisting of register banks. Common applications include interfacing with LCDs and 7-segment displays.