Series 308 Modular Potentiometer
Conductive Plastic—1/2" square
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| Description |
 The Series 308 is a high-performance, low-cost sealed Conductive Plastic potentiometer, available with switch and potentiometer modules with up to three sections. For equivalent units using thick-film cermet elements, see Series 309
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Compact: 1/2 in. (12.7mm) miniature, totally sealed, modular size
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Cost-effective: Sealed modules eliminate hand soldering.
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Rugged: Horizontal or vertical mountings with support plates. Nickel-plated brass shaft and bushings in various diameters and lengths. Insert molded gold plated terminals for strength.
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Precision Made: Screen-printed conductive plastic elements.
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Stable: -40°C to +120°C operating temperature.
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RoHS Compliant
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Shaft Styles: Plain, Slotted, Flatted, Concentric |
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Shaft Lengths from .025" minimum on trimmer to maximum of 3" (76.2mm) from bushing mounting surface
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Single shaft: .125"(3.18mm) dia. and .250"(6.35mm) dia. |
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Concentric shafts: .078"/.125"(1.98 / 3.18mm) dia. and .125"/.250"(3.18 / 6.35mm) dia. |
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Electrical Specifications
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Resistance Range
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Linear: 100 ohms to 5 megohms
Non-linear: 500 ohms to 2 megohms
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Resistance Tolerance
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Linear: ±10% (above 500K ±20%)
Non-linear: ±10% (above 100K ±20%)
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End Resistance
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Linear: 4 ohms max. each end.
Tapered: low side 4 ohms max.; high side 1% of total resistance.
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Voltage Coefficient
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.008% per Volt maximum
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Power Rating
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0.5 watt @ 70°C.
Derate linearly to zero watts at 120°C
Derate non-linear taper units by 50%
Derate tapered units, trimmers or PC mounted units by 50%
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Linearity Tolerance
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±5% independent
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Non-linear Tapers
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Linear: Right or left-hand available.
Non-Linear: Logarithmic or reverse Logarithmic.
Specials available.
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Taper Tolerance
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±20% of nominal resistance @ 50%; ±3% of mechanical rotation
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Electrical Rotation
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295° ±5°
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Effective Rotation
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265° ±5°
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Working Voltage
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350 VDC across end terminals
(power not to exceed rating)
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Dynamic Noise
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Standard: Linear single controls maximum initial noise level of 1.5% of total resistance. 1% available on special order
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Push Switch
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SPDT, 125ma @ 28Vdc, Push Momentary
(Type DJ)
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Rotary Switch
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SPST or SPDT, CCW or CW, 125ma @ 28Vdc.(Type AL)
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Mechanical Specifications
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Housing Material
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Thermoplastic polyester, blue. Mechanical (U.L. SE-O rating)
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Hardware Supplied
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Nut: brass, nickel-plated
Lockwasher: phosphorous bronze, nickel-plated
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Mechanical Rotation
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295° ±5° |
Rotational Life
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Life under load is 50,000 cycles (Linear control with plain bushing)
Trimmer life under load is 5,000 cycles
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Torque Range
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.20 to 3.0 oz. in. (Single module)
.3 to 3.5 oz. in. (Dual module)
.4 to 4.5 oz. in. (Triple)
Other torque options available.
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Torque Variation
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Within control .5 oz. in. maximum
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Stop Torque
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3 lb. in. minimum Mechanical (metal shaft)
Other torque options available
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Terminals
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Gold-coated PC terminals or solder hook style
PC pins fit .100 grid spacing
Terminal mounting options available
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Weight
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Metal shaft & bushing (approx.):
0.19 oz.(Single), .27 oz.(Dual), .35 oz.(Triple)
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Bushing Material
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Brass nickel plated
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Bushing Diameters
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Supplied in 1/4"-32 NEF 2A thread (6.35mm)
and 3.8"-32 NEF 2A thread (9.53mm)
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Bushing Lengths
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0.25 in. (6.35mm), .375 in. (9.53mm), .5 in. (12.7mm)
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Bushing Styles
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Plain, locking and trimmer
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Environmental Specifications
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Operating Temp
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-40°C to +120°C
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Storage Temp
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-55°C to +120°C
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Solvent Resistance
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Housing resistant to trichlorethylene, Chlorethene NU, Freon TMS, Freon TMC, toluene, MEK, ethyl acetate and gasoline.
For solvents not listed, please consult State Electronics
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