Some microphones require power because they contain an amplifier within the microphone. That is why you will notice that most high powered microphones have three coils at the male and female ends. These microphones use 48 volts of power (depending on the type of microphone) to amplify the sounds through such audio devices. It is important to know how to identify microphones that use phantom power because Ribbon and Dynamic Microphones do not need such power or 48 volts to function. Microphones that require phantom power are called Condenser Microphones. It's important to know that phantom power is not to be supplied to ribbon microphones because it may harm the microphone. When you look at a mixer you may see a button that says phantom power, this button is to be applied to microphones that use phantom power. Please note that the reason why it is called phantom power is because the power supply is invisible because it is built into the mixer.