A battery-powered, portable component of a sweat-induction iontophoresis system intended to produce a variable low-voltage current (e.g., 1.5mA) to induce sweating by facilitating the transcutaneous introduction of water-soluble electrolytic substances, typically containing pilocarpine, via applied skin electrodes. It typically functions automatically and is primarily used in the diagnosis of cystic fibrosis (CF). This is a reusable device.