This text leads the reader through several levels of complexity beginning
with simple circuits with a simple function and concluding with an introduction
to the use of servo valves to control heavy loads moving at high speed.
As we proceed along this journey, the reader will be periodically reminded
that the fundamental concept of fluid power is quite simple. Fluid power
technology is the conversion of mechanical energy to fluid energy, delivery
of this energy to a utilization point, and then its conversion back to mechanical
energy. A fluid power circuit has all three features: conversion from
mechanical energy to fluid energy, delivery, and conversion from fluid
energy back to mechanical energy. An electrical circuit also has all three features,
but often the designer focuses only for the final conversion step—electrical-to-mechanical. Generation of the electrical energy and its delivery are
external to the design problem.