  Feynman's ratchet and pawl is a paradigmatic model for energy conversion
using thermal fluctuations in the mesoscopic regime. Here, we optimize the
power output of the ratchet as a heat engine in the high temperatures limit,
and derive the universality of efficiency at maximum power up to second order,
using a non-linear approximation. On the other hand, the linear model may be
optimized by constraining the internal energy scales in different ways. It is
shown that simple constraints lead to well-known expressions of thermal
efficiency in finite-time thermodynamics. Thereby, the constrained ratchet, in
the linear regime, has been mapped to an effective finite-time thermodynamic
model.
