The benefits derived from the development of acoustic transistors which act as switches or amplifiers
have been reported in the literature. Here we propose a model of acoustic switch. We theoretically demonstrate
that the device works: the input signal is totally restored at the output when the switch is on
whereas the output signal nulls when the switch is off. The switch, on or off, depends on a secondary
acoustic field capable to manipulate the main acoustic field. The model relies on the attenuation effect
of many oscillating bubbles on the main travelling wave in the liquid, as well as on the capacity of the
secondary acoustic wave to move the bubbles. This model evidences the concept of acoustic switch (transistor)
with 100% efficiency.