Stimulator, Electronic

a generator for applying an electric current to excitable biological systems—organs and tissues.

Electronic stimulators are used therapeutically in the electrostimulation of the heart (mainly in cases of arrhythmia) and of skeletal and visceral muscles (for example, of the sphincter of the urinary bladder). They are also used in diagnosing diseases of the nervous and muscular systems. The two major types— neurostimulators and cardiostimulators—may be stationary, portable (usually battery-powered), or implanted into the body of an experimental animal or an individual requiring this type of device.

Modern electronic stimulators contain several generators powered by vacuum tubes and transistors and emit pulses of different shapes, including square-wave, sinusoidal, sawtooth, and bell-shaped pulses. Most frequently used are stimulators that emit square-wave pulses, which are most similar in shape to nerve impulses. An electron-optical generator that emits pulses of any shape has been developed for delicate biophysical experiments. The pulses applied to biological objects may be solitary or paired (of the same or different polarities) and may come continuously or in periodic pulse trains with different pulse repetition frequencies and quantity of pulses. Electronic stimulators are equipped with output separation circuits to prevent pulses from the stimulator from interfering with the discharging and recording of bioelectric potentials that arise in response to stimulation.