  A field-effect transistor (FET) amplifier for small voltage signals is
presented. Its design is elementary and the construction can be afforded by
anyone. Despite its simplicity, with a voltage noise less than 1 nV/sqrt(Hz),
it outperforms commercially available integrated FET amplifiers. The amplifier
has a gain flatness better than 1 dB over 1 MHz bandwidth; it can be employed
as a front-end for signal analyzers or signal recovery systems.
