A rheostat is a device which is used to vary the resistance in an electrical circuit without interrupting the circuit.heostats are a kind of potentiometer. These devices can be used in a variety of settings, and are usually designed to be sealed so that environmental factors cannot interfere with the function of the circuit.
This chemical can cause allergic rhinitis and its symptoms, including a runny nose, sneezing, and itchy eyes. In addition to tree pollen, other common allergens include: grass pollen
More detail and supporting information is in the main article. 1  Allergic rhinitis, often called hay fever, is a common condition that causes symptoms such as sneezing, stuffy nose, runny nose, watery eyes and itching of the nose, eyes or the roof of the mouth.