A double tuned amplifier is known as a Buffer amplifier and is capacitated for less level stages.
As the name suggests, this amplifier is the one that is an enabler in electrical impedance transformation from one circuit to the other. It aims to prevent the signal source from being adversely affected by fluctuating levels of electricity. The signal is ‘Buffered from’ load currents and therefore the specific name. These instruments are extensively used for boosting the current in any circuit at any stage.