Amplifier requires no dc bias

https://www.electronics-lab.com/amplifier-requires-no-dc-bias/

john guy @ edn.com writes: Intrinsically capacitive transducers and other high-impedance signal sources usually require ac coupling and a buffer amplifier to condition the signal for further processing. Buffers take many forms, but most of them compromise signal quality through the use of external resistors that provide a dc path for the input bias current. […]