An interactive web application framework allows a user to define user interface and logic of a web application and publish the web application. A power-limited voltage converter steps up the wireline voltage to a higher \u2018isolating\u2019 voltage, charging a capacitor coupled to the ring generator. A field strength-programming interface may be at a middle level of abstraction and may include electromagnetic field-strength patterns generated by the stimulation zones, andor electrode settings, and a depiction of how the electromagnetic fields interact with each other. The diaphragm seal is flexible to allow for expansion and contraction of the chamber due to changes in temperature to prevent any substantial increase or decrease in the pressure within the chamber.