運算放大器

An operational amplifier (op amp) is a voltage amplifying device with differential inputs, single ended outputs and high gain intended for use with external feedback elements where these elements determine the resultant function or operation. An op amp consists of multiple transistors packaged in an integrated circuit chip. It senses the fluctuating voltage difference between two inputs, uses power from an external supply to amplify that difference, and uses negative feedback to ensure that the output is an accurate replica of the input. Its amplification can be adjusted by changing the values of two external resistors.