Operational amplifiers (op-amps) are linear integrated circuits used in applications such as communication and medical electronics to sense and amplify signals. An op-amp consists of transistors, resistors, and a capacitor, and has two inputs and a single output. There are several configurations of op-amps including inverting amplifiers, non-inverting amplifiers, summing amplifiers, and difference amplifiers. Logic gates are digital circuits with one or more inputs and one output that processes digital signals. Common logic gates include OR, AND, NOT, NAND, NOR, and EXOR gates.