A power microphone is used to amplify your voice that you speak into the mic. Then that voice then gets amplified by the amplifier power circuit inside the microphone, overall making your voice sound louder and clear and can trick people into thinking you have a $400 dollar CB radio. Then your voice is sent into the CB radio to transmit it on the air waves, louder with more clarity, if compared to a standard cb radio mic. A power mic is relevant if you have increase the modulation inside your CB radio and there is no significant gain in gaining more modulation. Inside a power mic, a 9 volt battery is required for the amplifier circuit. So power microphones have a built in echo feature, which is adjustable, so you can sound unique on the air waves.
