Features Non-standard features and 7/8 (22 mm) diameter single-turn specifications available conductive plastic Bushing mount Excellent resolution High rotational life ball bearing shaft support 6638 - Precision Potentiometer 1 Electrical Characteristics Product Dimensions Standard Resistance Range....................................................................................1 K to 100 K ohms Total Resistance Tolerance .........................................................................................................10 % 6638 Independent Linearity ...................................................................................................................1 % 7/8 (22 mm) DIA. 2 Effective Electrical Angle .......................................................................................................340 3 5.08 End Voltage .................................................................................................................0.5 % maximum R CW (.20) Output Smoothness ....................................................................................................0.1 % maximum Dielectric Withstanding Voltage (MIL-STD-202, Method 301) 3 1 Sea Level .............................................................................................................750 VAC minimum Power Rating (Voltage Limited By Power Dissipation or 300 VAC, Whichever is Less) +70 C......................................................................................................................................1 watt +125 C....................................................................................................................................0 watt Insulation Resistance (500 VDC)..................................................................1,000 megohms minimum 45 5 1.57 Resolution..................................................................................................................Essentially infinite (.062) 13.64 .38 7.14 + .00/- .05 DIA. 1 (.281+.000/-.002) (.537 .015) Environmental Characteristics 1/4 -32 UNEF-THD Operating Temperature Range...................................................................................+1 C to +125 C 3.170 + .000/-.008 Storage Temperature Range.....................................................................................-65 C to +125 C DIA. (.1248+.0000/.0003) Temperature Coefficient Over Storage Temperature Range...........................500 ppm/C maximum .25 45 5 X Vibration .........................................................................................................................................15 G (.010) CHAMFER Wiper Bounce...........................................................................................0.1 millisecond maximum 22.23 Total Resistance Shift ..............................................................................................5 % maximum (7/8) Voltage Ratio Shift ................................................................................................0.5 % maximum DIA. Shock .............................................................................................................................................50 G Wiper Bounce...........................................................................................0.1 millisecond maximum 9.53 Total Resistance Shift ..............................................................................................5 % maximum 3.18 (3/8) Voltage Ratio Shift ................................................................................................0.5 % maximum (1/8) 22.23 Load Life.................................................................................................................1,000 hours, 1 watt (7/8) Total Resistance Shift ............................................................................................10 % maximum .38 Rotational Life (No Load) .........................................................................20,000,000 shaft revolutions SHAFT SLOT (.015) .81 .81 Total Resistance Shift ............................................................................................10 % maximum WIDE X DEEP (.032) (.032) Moisture Resistance (MIL-STD-202, Method 106) Total Resistance Shift ............................................................................................10 % maximum TOLERANCES: EXCEPT WHERE NOTED IP Rating ........................................................................................................................................IP 40 .51 .127 DECIMALS: .XX .XXX (.02), (.005) 1 Mechanical Characteristics FRACTIONS: 1/64 MM Mechanical Angle ................................................................................................................Continuous DIMENSIONS: (IN.) Torque (Starting & Running)............................................................0.18 N-cm (0.25 oz.-in.) maximum Mounting.............................................................................170-200 N-cm (15-18 lb.-in.) maximum Shaft Runout................................................................................................0.025 mm (0.001 in.) T.I.R. WIPER Shaft End Play ...............................................................................................0.13 mm (0.005 in.) T.I.R. 2 Shaft Radial Play ...........................................................................................0.08 mm (0.003 in.) T.I.R. Backlash ........................................................................................................................0.1 maximum CCW CW 3 1 Weight..........................................................................................................................................18 gm CLOCKWISE Terminals.......................................................................................................................Rear turret type Soldering Condition Manual Soldering................................96.5Sn/3.0Ag/0.5Cu solid wire or no-clean rosin cored wire 370 C (700 F) max. for 3 seconds Wave Soldering ........................................................96.5Sn/3.0Ag/0.5Cu solder with no-clean flux Recommended Part Numbers 260 C (500 F) max. for 5 seconds Wash processes ..................................................................................................Not recommended Resistance Marking ................................Manufacturers name and part number, resistance value and tolerance, Part Numbers () linearity tolerance, wiring diagram, and date code Ganging (Multiple Section Potentiometers).................................................................1 cup maximum 6638S-1-102 1,000 Hardware ...................................................One lockwasher (H-37-1) and one mounting unit (H-38-1) is shipped with each potentiometer. 6638S-1-502 5,000 6638S-1-103 10,000 BOLDFACE LISTINGS ARE IN STOCK AND READILY 1 At room ambient: +25 C nominal and 50 % relative humidity, except as noted. AVAILABLE THROUGH DISTRIBUTION. FOR OTHER OPTIONS CONSULT FACTORY. REV. 10/19 *RoHS Directive 2015/863, Mar 31, 2015 and Annex. WARNING Specications are subject to change without notice. Users should verify actual device performance in their specic Cancer and Reproductive Harm applications. The products described herein and this document are subject to specic legal disclaimers as set forth on the www.P65Warnings.ca.gov last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf. *RoHS COMPLIANTLegal Disclaimer Notice This legal disclaimer applies to purchasers and users of Bourns products manufactured by or on behalf of Bourns, Inc. and )V Y UZ P Z HSPH LZ JVSSLJ P LS Unless otherwise expressly indicated in writing, Bourns products and data sheets relating thereto are subject to change LU LSL HU PUMVYTH PVU HUK LYPM OH Z JO PUMVYTH PVU PZ J YY P OV UV PJL <ZLYZ ZOV SK JOLJR MVY HUK VI HPU OL SH LZ Y and complete before placing orders for Bourns products. 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