summary
● Direct-coupled amplifiers are used primarily as voltage amplifiers.
● A differential amplifier has two separate inputs and may provide either one or two outputs.
● Audio amplifiers amplify AC signals in the audio range of 20 to 20,000 hertz.
● The two types of audio amplifiers are voltage amplifiers and power amplifiers.
● Video amplifiers are wideband amplifiers used to amplify video information.
● Video frequencies extend from a few hertz to 5 or
● RF amplifiers operate from 10,000 hertz to 30,000 megahertz.
● The two types of RF amplifiers are tuned and untuned.
● Op-amps may provide output gains of 20,000 to 1,000,000 times the input.
● The two basic closed-loop modes are the inverting configuration and the noninverting configuration.