An assembly of portable, battery-powered devices designed to apply noninvasive cranial electrical stimulation (CES) via cranial/peripheral nerves in/around the external ear for the treatment of one or more psychiatric and stress-related disorders (e.g., anxiety, depression, insomnia, migraine); it might additionally be intended for the treatment of autoimmune diseases (e.g., rheumatoid arthritis). It consists of an external pulse generator (EPG) with controls/display, and transcutaneous electrodes for placement on the skin surface in/around the external ear. The device may be used in conjunction with a smartphone for use by a patient and healthcare provider. This is a reusable device.