Ultrasonic radiation balance

摘要

A radiation balance for testing the power of ultrasonic transducers involves a balance mechanism wholly immersed in transmission liquid in a windowed vessel to avoid surface tension effects. The mechanism comprises a target connected for movement with the coil of a moving coil/magnet assembly, such as from a galvanometer, and a null-seeking servomechanism energizes the coil in response to balance mechanism movement. The balance movement is about a vertical axis to avoid gravitational effects, and the target has neutral buoyancy.