Plastic materials in telephone use

Plastics are used extensively in the manufacture of telephone apparatus and equipment. They belong to the class of materials known as insulators but are very often employed not only for their electrical properties but for their unique manufacturing and structural possibilities. Good insulating materials are very important in the telephone field although the voltage and current used are much smaller than in the power field. Progressive improvement in transmission, especially for long distance telephone service, has required that the telephone industry as a whole provide sensitive instruments and that there be a minimum loss of the electrical impulse due to leakage through insulating materials.