Mica Trimmers & Padders

Trimmer Ranges I Printed Circuit I Padders

I ST Dimensions I

STANDARD TRIMMERS These variable compression mica trimming capacitors are produced by stacking mica dielectric capacitance units. A capacitor section consists of a thin film of mica between two spring loaded nonferrous metal conducting plates: the stacked units are mounted within a ceramic container, or on a ceramic base. By alternating metal plate, mica film, metal plate, ect., and paralleling these units, any desired capacitance within the physical limitations of the ceramic base can be achieved. A panhead adjusting screw (#2-64, UNS-2) thread for types 40 and 42 and a (#4-64, UNS-2) thread for type 46 is inserted through the center holes of the plates, the mica films, and the threaded bushing. This screw provides variable compression on the formed metal plates, varying the plate separation capacitance. Arco trimming capacitors are treated for resistance to humidity and for permanence of capacity setting. The base is made of the lowest loss ceramic dielectric available and the mica is clear India Ruby. The soldering lugs may be bent in any position without affecting the capacitance setting. Trimmers shown are standard sizes and capacities. Standard dimensional adjustment tolerance is +/- 3/32" or 3 1/2, whichever is applicable. Terminals having several lugs can be spot welded together to prevent separation and flaring. TYPE DESIGNATION EXAMPLE: ST 0423 1) Mounting Style: Abbreviations are defined below ----------ST = Standard Bracket Mounting Style ----------PC = Printed Circuit Mounting ----------C = Variation of Printed Circuit Mounting Style 2) The numbers indicates shape, construction, dimensions, and capacitance. SPECIFICATIONS OPERATING TEMPERATURE: -35C to +/-85C MAXIMUM CAPACITANCE: Equal to, or greater than the value indicated in the table. When the adjusting screw is at a tight position (with tight being defined as 1 3/4 pound-inches). The maximum capacitance will be equal to or greater than the value indicated in the table. MINIMUM CAPACITANCE: Equal to or less than, the value indicated in the table, when the adjusting screw is rotated three times from the tight position. DC VOLTAGE: Type 30 = 250V (rated): 500v (test) Types 40, 42, 46 = 175V (rated); 350v (test) Type 30M = 500V (rated); 1000v (test) INSULATION RESISTANCE: 100,000 meg-ohms minimum @ 20*C DISSIPATION FACTOR @ 1 KHz : 1000 puff max.; D.F. .004 max. CAPACITANCE CHANGE WITH TEMPERATURE* : Type 30 = +/-(2.5% + 0.3pF) Types 40, 42, 46 = +/-(1.5% to 0.3pF) CAPACITANCE DRIFT WITH TEMPERATURE* : Type 30 = +/-(2.0% + 0.5pF) Types 40, 42, 46 = +/-(1.5% to 0.5pF) ****screw adjusted 1/4 - 1/2 turn from tight

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