Passive Care Exam 1 Electrical Stimulation Practice Test

Instantaneous current and accumulated charge are distinct ideas in electrical stimulation safety. Net current is the instantaneous flow of charge at a specific moment, whereas net charge is the total amount of charge delivered over time, found by integrating the current waveform. This distinction matters because tissue safety hinges on how much charge actually accumulates at the electrode–tissue interface. If the waveform delivers unequal positive and negative charge, charge can build up, driving unwanted electrochemical reactions and tissue irritation. Balanced, biphasic currents are used precisely because they pair positive and negative phases so that the charges cancel over each cycle, keeping the net charge near zero and reducing risk to tissue. Even when the instantaneous current peaks, what protects tissue is maintaining charge balance over time.