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Properties of PYREX Radio Insulators
The isolation of radio frequency currents and their confinement within
definite circuits demands the use of non-conducting materials possessing an
unusual combination of electrical and physical characteristics.
Radio frequency currents tend to wander and leak over
to adjacent conductors, and materials which may offer a fairly effective
barrier to the passage of current of low frequency sometimes prove to be
conductors, or at least inefficient insulators, at radio frequencies.
Essential properties for satisfactory radio insulation
are low power loss, low surface conductivity, high electrical resistance, a
hard smooth surface, stability against corrosive influences, and a high
These properties must remain permanent and unchanged by
age, exposure to the elements, and the continued impact of radio energy.
Performance, which alone has won for PYREX Radio
Insulators their present day supremacy, is the direct result of the inherent
properties of the glass composition from which they are made.
The di-electric strength, 35 kv. per 100 mil
thickness is higher than that of the best grades of porcelain. The
di-electric constant, 4.48 at 30,000 cycles, and the
power factor, 0.28% at 30,000 cycles, are lower than those of any other
material now available for radio insulation, with the possible exception of
pure fused quartz. The surface conductivity is so low as to be
The specific gravity is 2.25, so that in PYREX
Radio Insulators, the dual advantages of light weight and high electrical
strength are combined.
The perfection of surface of PYREX Radio Insulators is
an important factor in preserving their continuous efficiency. Except in heavy
storms, rain does not form a continuous film on the surface, and as atmospheric
dust particles find no pores or cracks for permanent lodgment, a mild rainfall
washes away anything which may have settled on the insulator surface.