A medical implant can include a bioerodible metal portion and a coating overlying the bioerodible metal portion. The use of a reactive topcoat to thin the conductive paste avoids the need for hazardous volatile organic components as solvents to thin the conduct paste and improves the bonding of the conductive paste to the elastomeric substrate once the spray coating is cured. A control circuit is coupled between the positive and negative terminals of the capacitor, and this control circuit includes a switch that applies a variable control voltage to a relay in response to the position of the switch. At this time, the portion projecting from the lower surface of the first holding plate toward the substrate moves into the first hole.