Sound fields of circular transducers are basic in acoustics. The ring function method for the calculation of an emitted sound field by a plane or spherical transducer was introduced in 1974. Now, computer technology is developing rapidly. An event-driven program is available in personal computer systems such as ``Windows 95.'' Then, a personal computational program for sound fields produced by circular transducers is developed. Computed images of sound fields are useful for understanding the features of emission of sound.