Each TYPE 510 Decade-Resistance Unit is enclosed in an aluminum shield, and a knob and etchedmetal dial plate are supplied. The assembly is also available complete except for resistors, as the TYPE 510-P3 and -P3L Switches.
The TYPE 1432 Decade Resistor is an assembly of TYPE 510 Decade-Resistance Units in a single cabinet, Mechanical as well as electrical shielding of the units and switch contacts is provided by the attractive aluminum cabinet and panel. The resistance elements have no electrical connection to the cabinet and panel, for which a separate shield terminal is provided.
Each decade has eleven contact studs and ten resistors, so that the dial values overlap. Positive detent mechanisms and bar-type knobs permit the operator to sense the position of the switches without looking at the panel. Each resistor is adjusted to be accurate within its specified tolerance at its terminals, so that resistance increments are accurate to that tolerance. Winding methods are chosen to reduce the effects of residual reactances. The 1-ohm steps are Ayrton-Perry
wound on molded phenolic forms especially shaped and heat treated to minimize aging effects. The 10- and 100-ohm
steps are Ayrton-Perry wound on a form of silicone-fiberglas laminate. The 0.01- and 0.1-ohm steps are straight wire and hairpin-shaped ribbon, respectively, while the 1000-, 10,000-, 100,000-, and 1,000,000-ohm steps are unifilar wound on thin mica cards.
