REV. 10/08
*RoHS Directive 2002/95/EC Jan 27 2003 including Annex
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
6638 - Precision Potentiometer
Features
■7/8 ” (22 mm) diameter single-turn
conductive plastic
■Bushing mount
■Excellent resolution
■High rotational life – ball bearing
shaft support
■Non-standard features and
specifications available
Electrical Characteristics1
Standard Resistance Range....................................................................................1 K to 100 K ohms
Total Resistance Tolerance .........................................................................................................±10 %
Independent Linearity ...................................................................................................................±1 %
Effective Electrical Angle.......................................................................................................340 ° ±3 °
End Voltage .................................................................................................................0.5 % maximum
Output Smoothness ....................................................................................................0.1 % maximum
Dielectric Withstanding Voltage (MIL-STD-202, Method 301)
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
Resolution..................................................................................................................Essentially infinite
Environmental Characteristics1
Operating Temperature Range...................................................................................+1 °C to +125 °C
Storage Temperature Range.....................................................................................-65 °C to +125 °C
Temperature Coefficient Over Storage Temperature Range...........................±500 ppm/°C maximum
Vibration .........................................................................................................................................15 G
Wiper Bounce...........................................................................................0.1 millisecond maximum
Total Resistance Shift ..............................................................................................±5 % maximum
Voltage Ratio Shift ................................................................................................±0.5 % maximum
Shock .............................................................................................................................................50 G
Wiper Bounce...........................................................................................0.1 millisecond maximum
Total Resistance Shift ..............................................................................................±5 % maximum
Voltage Ratio Shift ................................................................................................±0.5 % maximum
Load Life.................................................................................................................1,000 hours, 1 watt
Total Resistance Shift ............................................................................................±10 % maximum
Rotational Life (No Load) .........................................................................20,000,000 shaft revolutions
Total Resistance Shift ............................................................................................±10 % maximum
Moisture Resistance (MIL-STD-202, Method 106)
Total Resistance Shift ............................................................................................±10 % maximum
IP Rating ........................................................................................................................................IP 40
Mechanical Characteristics1
Mechanical Angle ................................................................................................................Continuous
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.
Shaft End Play ...............................................................................................0.13 mm (0.005 in.) T.I.R.
Shaft Radial Play ...........................................................................................0.08 mm (0.003 in.) T.I.R.
Backlash ........................................................................................................................0.1 º maximum
Weight..........................................................................................................................................18 gm
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
260 °C (500 °F) max. for 5 seconds
Wash processes ..................................................................................................Not recommended
Marking ................................Manufacturer’s name and part number, resistance value and tolerance,
linearity tolerance, wiring diagram, and date code
Ganging (Multiple Section Potentiometers).................................................................1 cup maximum
Hardware ...................................................One lockwasher (H-37-1) and one mounting unit (H-38-1)
is shipped with each potentiometer.
Recommended Part Numbers
Part Numbers Resistance
(Ω)
6638S-1-102 1,000
6638S-1-502 5,000
6638S-1-103 10,000
BOLDFACE LISTINGS ARE IN STOCK AND READILY
AVAILABLE THROUGH DISTRIBUTION.
FOR OTHER OPTIONS CONSULT FACTORY.
13CW
CLOCKWISE
CCW
2WIPER
6638
7/8 " (22 mm) DIA.
1/4"-32 UNEF-THD
3
2
1
CW
45 ° ± 5 °
5.08
(.20)
R
13.64 ± .38
(.537 ± .015)
1.57
(.062)
22.23
(7/8)
DIA.
7.14 + .00/- .05
(.281+.000/-.002)
DIA.
DIA.
3.170 + .000/-.008
(.1248+.0000/.0003)
.25
45 ° ± 5° X (.010)
CHAMFER
3.18
(1/8)
.38
(.015)
9.53
(3/8)
SHAFT SLOT
(.032) WIDE X (.032) DEEP
.81 .81
22.23
(7/8)
TOLERANCES: EXCEPT WHERE NOTED
.51 .127
DECIMALS: .XX ± (.02), .XXX ± (.005)
FRACTIONS: ±1/64
MM
DIMENSIONS: (IN.)
1At room ambient: +25 °C nominal and 50 % relative humidity, except as noted.
Product Dimensions
*RoHS COMPLIANT
