ABSTRACT
This chapter reviews some of the physical concepts that underlie the interaction between electric fields and biological materials with the objective of providing background for determining safe levels of exposure and new applications for the use of electricity in therapy. It describes the rectification process at the cell membrane in some detail and shows that cell non-linearities lead to frequency-dependent effects such as injection phase locking of pacemaker cells. The chapter briefly examines some problems associated with the exposure of cells to very low, extremely low-frequency (ELF) fields and the application of large ELF fields to biological systems. It suggests that the values for the electric and magnetic field at the desired location in the biological system can either be calculated from Maxwell's equations or measured. The force equations are used to develop equations for the conductivity and the dielectric constant.
