MODEL 78 1 1-1/4” Rectangular Multiturn Cermet Trimming Potentiometer ELECTRICAL Standard Resistance Range, Ohms Standard Resistance Tolerance Input Voltage, Maximum Slider Current, Maximum Power Rating, Watts End Resistance, Maximum Actual Electrical Travel, Turns, Nominal Dielectric Strength Insulation Resistance, Minimum Resolution Contact Resistance Variation, Maximum 10 to 2Meg ±10% (<100 Ohms = ±20%) 300 Vdc or rms not to exceed power rating 100mA or within rated power, whichever is less 1.0 at 70°C derating to 0 at 125°C 2 Ohms 22 500 Vrms 1,000 Megohms Essentially infinite 1% or 1 Ohm, whichever is greater ENVIRONMENTAL Seal Temperature Coefficient, Maximum Operating Temperature Range Thermal Shock Moisture Resistance Shock, 6ms Sawtooth Vibration High Temperature Exposure Rotational Life Load Life at 0.5 Watts Resistance to Solder Heat 85°C Fluorinert® (No Leaks) ±100ppm/°C –55°C to +125°C 5 cycles, –55°C to +125°C (1% ∆RT, 1% ∆VR) Ten 24 hour cycles (1% ∆RT, IR 1,000 Megohms Min.) 100G’s (1% ∆RT, 1% ∆VR) 20G’s, 10 to 2,000 Hz (1% ∆RT, 1% ∆VR) 250 hours at 125°C (2% ∆RT, 2% ∆VR) 200 cycles (3% ∆RT) 1,000 hours at 70°C (2% ∆RT) 260°C for 10 sec. (1% ∆RT) MECHANICAL Mechanical Stops Torque, Starting Maximum Weight, Nominal Clutch Action, both ends 5oz.-in. (0.035 N-m) .09 oz. (2.6 grams) Fluorinert® is a registered trademark of 3M Company. Specifications subject to change without notice. 1-61 Model 78 SIDE ADJUSTMENT (Inch/mm) Model 78P Circuit Diagram Marked On This Surface Housing Molded Plastic Model No. & Resistance Value Marked On This Surface 0.07 1.78 1.25 31.75 1.000 ± .005 25.400 ± 0.127 .015 ± .003 0.127 ± 0.076 2 Mounting Holes .093 ± .005 I.D. 2.362 ± 0.127 Metal Adjustment Screw .110/2.794 ± 0.127 Dia. With .025/0.635 ± 0.127 Wide X .031/0.787 ± 0.127 Deep Slot (1) (2) .125 ± .005 3.175 ± 0.127 .105 2.667 .32 8.13 .135 .50 ± .03 (3) 3.429 12.70 ± 0.76 .195 ± .005 4.953 ± 0.127 3 Terminals Pins Solderable .028 ± .003 Dia. 0.711 ± 0.076 .05 1.27 .10 2.54 .30 7.62 .260 ± .015 6.604 ± 0.381 .70 17.78 Note: Model 78P dimensions applicable to all other models except as noted. Model 78L .062/1.575 Max. Meniscus 3 Electrical Leads – 6/152 Min. Length No. 30 AWG Teflon Insulated Stranded Wire Yellow (1) Red (2) Green (3) .187 ± .031 4.750 ± 0.787 Model 78S .156 ± .031 Dia. 3.962 ± 0.787 (3 Places) .70 ± .02 17.78 ± 0.51 (1) (2) (3) .30 ± .02 7.62 ± 0.51 .26 ± .02 6.60 ± 0.51 1-62 3 Terminals Pins Solderable .028 ± .003 Dia. 0.711 ± 0.075 .05 ± .02 1.27 ± 0.51 .10 ± .02 2.54 ± 0.51 Model 78 PANEL MOUNT ADAPTER (Inch/mm) 1 Model 56BW (Adapter Only) Metal Bushing Mount Brass-Nickel Plated Mounting Surface .125 ± .005 Dia. Hole 3.175 ± 0.127 Use .22/5.613 Dia. Min. Mounting Hole Lock Washer, Panel Nut, Sealing Washer & Mounting Screws Provided 1.56 Max. 3.962 .312 ± .015 7.925 ± 0.381 .437 Max. 11.100 Model 78LBW (Adapter Pre-Assembled with Trimmer) 0.94 Max. 2.388 .250 ± .015 6.350 ± 0.381 1.344 Max. 34.138 12-28 UNF-2A Thread Model 78SBW (Adapter Pre-Assembled with Trimmer) 0.94 Max. 2.388 .250 ± .015 6.350 ± 0.381 1.344 Max. 34.138 (1) (2) (3) 12-28 UNF-2A Thread .344 ± .031 8.738 ± 0.787 1-63 Model 78 STANDARD RESISTANCE VALUES, OHMS 10 20 50 100 200 500 1K 2K 5K 10K 20K 25K 50K 100K 200K 250K 500K 1Meg 2Meg PACKAGING Standard: Boxes Capacity = 25 Units ORDERING INFORMATION 78 P BW R 10K LF RoHS Compliant Code - optional Resistance Value Resistance Prefix Optional Panel Mount Adapter Model Series Pin Style Note: Use ‘56BW’ to order panel mount adapter without trimmer NOTES CIRCUIT DIAGRAM Metric equivalents, based on 1 inch = 25.4mm are rounded to the same number of significant figures as in the original English units and are provided for general information only. (2) (1) (3) INCH mm Tolerances unless otherwise specified: Linear = ± .01 inches (.25mm) Angular = ± 2 degrees CW 1-64 Model 78