Electrical stimulators that apply stimuli to the cochlea. These stimulators consist of an electrode array that is surgically inserted in one cochlea, a receiver that is implanted in the skull near the ear and connected to the electrode array, and a speech transducer that is worn externally. The speech transducer converts sound into electrical signals that are transmitted to the receiver, which in turn stimulate the cochlea through the electrode array. These stimulators are used for the partial restoration of auditory sensation to profoundly deaf patients.