Features
■ Non-standard features and
specifications available
■ 7/8 ” (22 mm) diameter single-turn
conductive plastic
■ Bushing mount
■ Excellent resolution
■ High rotational life – ball bearing
shaft support
6638 - Precision Potentiometer
Electrical Characteristics1
Product Dimensions
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)
6638
7/8 " (22 mm) DIA.
2
5.08
(.20)
R
CW
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
Resolution..................................................................................................................Essentially infinite
45 ° ± 5 °
1.57
(.062)
7.14 + .00/- .05
(.281+.000/-.002)
1/4"-32 UNEF-THD
13.64 ± .38
(.537 ± .015)
DIA.
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 ppmꢁ°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)
3.170 + .000/-.008
DIA.
(.1248+.0000/.0003)
.25
45 ° ± 5° X
(.010)
CHAMFER
22.23
(7/8)
DIA.
9.53
(3/8)
3.18
(1/8)
22.23
(7/8)
.38
(.015)
SHAFT SLOT
.81
(.032)
.81
WIDE X
DEEP
(.032)
Total Resistance Shift ............................................................................................ 10 ꢀ maximum
IP Rating........................................................................................................................................IP 40
TOLERANCES: EXCEPT WHERE NOTED
.51
(.02),
.127
(.005)
DECIMALS: .XX ±
FRACTIONS: ±1/64
.XXX ±
Mechanical Characteristics1
MM
(IN.)
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
DIMENSIONS:
WIPER
2
CW
CCW
3
1
CLOCKWISE
Manual Soldering................................96.5Snꢁ3.0Agꢁ0.5Cu solid wire or no-clean rosin cored wire
370 °C (700 °F) max. for 3 seconds
Wave Soldering ........................................................96.5Snꢁ3.0Agꢁ0.5Cu solder with no-clean flux
260 °C (500 °F) max. for 5 seconds
Recommended Part Numbers
Wash processes ..................................................................................................Not recommended
Marking ................................Manufacturer’s name and part number, resistance value and tolerance,
linearity tolerance, wiring diagram, and date code
Resistance
Part Numbers
(Ω)
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.
6638S-1-102
6638S-1-502
6638S-1-103
1,000
5,000
10,000
BOLDFACE LISTINGS ARE IN STOCK AND READILY
AVAILABLE THROUGH DISTRIBUTION.
1At room ambient: +25 °C nominal and 50 % relative humidity, except as noted.
FOR OTHER OPTIONS CONSULT FACTORY.
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.