Features
n Single-turn (3851 and 3852)
n 3-3/4-turn (3856)
n Linear and audio tapers
n Wide resistance range
n Minimal depth package
n Good resolution
3851/3852/3856 – 3/4 ˝ Diameter Panel Control
Initial Electrical Characteristics1
3851 3852/3856
Conductive Plastic Element
Cermet Element
Standard Resistance Range
Linear Tapers (A, B, E, and H).....................1 K to 1 megohm...............................................100 ohms to 1 megohm
Audio Tapers (C, D, F, and G)......................1 K to 1 megohm...............................................1 K ohms to 1 megohm
Total Resistance Tolerance................................±10 % or ±20 %.................................................±5 % or ±10 %
Independent Linearity........................................±10 %................................................................(A & H tapers) ±5 %
Absolute Minimum Resistance..........................2 ohms maximum.............................................. 2 ohms maximum
Effective Electrical Angle...................................(Linear tapers) 250 ° ±5 °..................................(Linear tapers) 250 ° ±5 °
(Audio tapers) 225 ° ±5 °...................................(Audio tapers) 225 ° ±5 °
Contact Resistance Variation............................±1 %..................................................................±3 % of total resistance or 3 ohms
(whichever is greater)
Dielectric Withstanding Voltage (MIL-STD-202, Method 301)
Sea Level.....................................................900 VAC minimum.............................................900 VAC minimum
70,000 Feet..................................................350 VAC minimum.............................................350 VAC minimum
Insulation Resistance (500 VDC)......................1,000 megohms minimum.................................1,000 megohms minimum
Power Rating (Voltage Limited By Power Dissipation or 350 VAC, Whichever Is Less)
+70 °C .........................................................(Linear tapers) 1 watt........................................(Linear tapers) 2 watts
(Audio tapers) 0.5 watt......................................(Audio tapers) 1 watt
+125 °C........................................................0 watt
+150 °C..................................................................................................................................0 watt
Theoretical Resolution.......................................Essentially infinite..............................................Essentially infinite
Environmental Characteristics1
Operating Temperature Range........................... -1 °C to +125 °C.................................................. -1 °C to +125 °C
Storage Temperature Range.............................. -65 °C to +125 °C................................................ -65 °C to +150 °C
Temperature Coefficient Over
Storage Temperature Range............................ ±1,000 ppm/°C.................................................... ±150 ppm/°C
Vibration.............................................................. 20 G..................................................................... 20 G
Total Resistance Shift.................................... ±2 % maximum................................................... ±2 % maximum
Voltage Ratio Shift......................................... ±5 % maximum................................................... ±6 % maximum
Shock.................................................................. 100 G................................................................... 100 G
Total Resistance Shift.................................... ±2 % maximum................................................... ±2 % maximum
Voltage Ratio Shift......................................... ±5 % maximum................................................... ±6 % maximum
Load Life............................................................. 1,000 hours......................................................... 1,000 hours
Total Resistance Shift.................................... ±10 % maximum................................................. ±3 % maximum
Rotational Life (No Load).................................... 100,000 cycles.................................................... 20,000 cycles
Total Resistance Shift.................................... ±15 % TRS maximum ........................................ ±5 % or 5 ohms TRS whichever is greater
Contact Resistance Variation........................ ±3 %.................................................................... ±3 %
Moisture Resistance (MIL-STD-202, Method 103, Condition B)
Total Resistance Shift.................................... ±10 % maximum ................................................ ±2 % maximum
IP Rating.............................................................. IP 40.................................................................... IP 40
1 Electrical
specifications tested at 250 RPM, at room ambient: +25 °C nominal.
WARNING
Cancer and Reproductive Harm
www.P65Warnings.ca.gov
*RoHS Directive 2015/863, Mar 31, 2015 and Annex.
Specifications are subject to change without notice. Users should verify actual device performance in their specific
applications. The products described herein and this document are subject to specific legal disclaimers as set forth on the
last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
3851/3852/3856 – 3/4 ˝ Diameter Panel Control
Mechanical Characteristics1
Stop Strength
3851 & 3852������������������������������������������������������������������������������������������������������������������������������������������������������������������56.5 N-cm (5 lb.-in.)
3856������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� Continuous turn
Mechanical Angle�������������������������������������������������������������������������������������������������������������������������������������������� 280 ° ±5 ° / 3856 – 1350 ° ±50 °
Torque (Starting and Running)������������������������������������������������������������������������������������� A & B bushings 0.35 to 4.23 N-cm (0.05 to 6.0 oz.-in.)
.
C & E bushings 0.21 to 4.23 N-cm (0.3 to 6.0 oz.-in.)
.
3856 – 0.11 to 2.12 N-cm (0.15 to 3.0 oz.-in.)
Mounting (Torque on Bushing)����������������������������������������������������������������������������������������������������������� 1.7-2.0 N-m (15-18 lb.-in.) maximum
Weight (Single Section)������������������������������������������������������������������������������������������������������������������������������������������������������30 grams maximum
Terminals������������������������������������������������������������������������������������������������������������������������������������������������ Printed circuit terminals or solder lugs
Soldering Condition��������������������������������������������Recommended hand soldering using Sn95/Ag5 no clean solder, 0.025 ˝ wire diameter.
.
Maximum temperature 399 °C (750 °F) for 3 seconds. No wash process to be used with no clean flux.
.
Part can be wave soldered at 260 °C (500 °F) for 5 seconds, no wash process with no clean flux.
Marking��������������������������������������������������������������������������Manufacturer’s trademark, wiring diagram, resistance, date code, and part number
Ganging (Multiple Section Potentiometers)������������������������������������������������������������������������������������������������������������������������������1 cup maximum
Hardware������������������������������������������������������������������������������������ One lockwasher and one mounting nut is shipped with each potentiometer;
locking bushing versions are shipped with one additional locking nut
(Bushing A&H: H-37-2 & H-38-2; Bushing B: H-37-2, H-38-2 & H-38-4; Bushing C: H-37-1 & H-38-1;
Bushing E: H-37-1, H-38-1 & H-38-3)
1 Electrical
specifications tested at 250 RPM, at room ambient: +25 °C nominal.
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
3851/3852/3856 – 3/4 ˝ Diameter Panel Control
Product Dimensions
6.35 ± .76
(.25 ± .03)
12.7, 22.23
STD.
(1/2, 7/8)
9.53
(.38)
3/8-32 UNEF
.25
45 ° X
(.010)
CHAMFER
.38
(.015)
19.05
(.75)
DIA.
6.35+.03/-.05
DIA.
(.250+.001/-.002)
6.35 ± .76
(.25 ± .03)
3/8-32 UNEF
.25
45 ° X
(.010)
CHAMFER
.38
(.015)
19.05
(.75)
DIA.
SHAFT SLOT
1.19
.047 WIDE X
1.60+.38/.00
DEEP
(.063+.015/-.000)
12.19
DIA.
(.480)
15.88
STD.
(5/8)
12.7
(.50)
6.35+.03/-.05
DIA.
(.250+.001/-.002)
SHAFT SLOT
1.19 WIDE X
(.047)
1.60+.38/-.00
(.063+.015/-.000)DEEP
12.19
DIA.
(.48)
16.00
5.49
OPTIONAL FLAT
(.63)
(.216)
1.52
28.58
LONG OR
FRONT BUSHING FOR SHAFTS UNDER
(.06)
(1-1/8)
SOLDER LUG TERMINAL
6.35
2.79
TYP.
(.25)
(.110)
3 PLCS.
12.7
(.50)
EACH TERMINAL LUG
2
3
2 PLCS. 1
WILL ACCOMMODATE
.72
THREE (.028) DIAMETER
14.02 ± .25
(.724 DIA. AWG
(.552 ± .010)
STRANDED) WIRES.
STANDARD
PRINTED CIRCUIT TERMINAL
1.02
6.35
TYP.
TYP.
(.040)
(.25)
15.88 ± .38
(.625 ± .015)
9.53, 22.23
STD.
(3/8, 7/8)
6.35
(.25)
6.35 ± .76
(.25 ± .03)
.38
(.015)
2.36
(.094)
19.05
(.75)
DIA.
1/4-32 UNEF
.25
45 ° X (.010)
CHAMFER
12.19
DIA.
(.480)
12.19
DIA.
(.480)
SHAFT SLOT
.79 WIDE X .76 DEEP
(.03)
(.031)
6.35 ± .76
(.25 ± .03)
3/8-32 UNEF
1.19
(.047)
19.05
(.75)
DIA.
12.19
DIA.
(.480)
1.60+3.81/-.000
(.063+.015/-.000)
DIA.
22.23
STD.
(7/8)
3.18 ± .025
DIA.
(.125 ± .001)
SHAFT SLOT
.79 WIDE X .76 DEEP
(.031)
(.03)
SUGGESTED BOARD LAYOUT
6.35
6.35
(.25)
(.25)
.25
45 ° X (.010)
CHAMFER
A, B & H BUSHINGS
9.53
(.375)
6.35 ± .76
(.25 ± .03)
.38
(.015)
C & E BUSHINGS
9.53
(.375)
3.18
6.73
DIA. (.125)DIA.
(.265)
3.18
DIA.
(.125)
SHAFT SLOT
ALIGNMENT
AT CCW
12.7
(.50)
9.53
(.38)
6.35+.03/-.05
DIA.
(.250+.001/-.002)
.38
(.015)
.25
45 ° X (.010)
CHAMFER
9.91
DIA.
(.390)
12.7
(.50)
6.35
(.25)
3
1.40
DIA.
(.055)
.25
OPTIONAL FLAT
LONG OR
(.010)
1.52
15.88
FRONT BUSHING FOR SHAFTS UNDER
(.06)
(5/8)
9.53
(.38)
1/4-32 UNEF
.38
(.015)
19.05
(.75)
DIA.
3.18 ± 0.25
DIA.
(.125 ± .001)
2
12.7
STD.
(1/2)
9.53
(.38)
6.35 ± .76
(.25 ± .03)
1
6.35+.03/-.05
DIA.
(.250 ± .03)
FLAT
ALIGNMENT
AT CCW
50 ° ± 10 °
50 ° ± 10 °
3/8-32 UNEF.
.79
(.031)
2.67 ± .381
(.105 ± .015)
19.05
(.75)
DIA.
12.19
DIA.
(.480)
.79 ± .25
(.031 ± .010)
22.23
STD.
(7/8)
DIMENSIONS:
MM
(INCHES)
3.18 ± .03
(.125 ± .003)
DIA.
.25
45 ° X (.010)
CHAMFER
ANTI-ROTATION LUG
PROJECTS 1/16 INCH
ABOVE MOUNTING FACE.
TOLERANCES EXCEPT AS NOTED:
.127
.XX ± .38
DECIMALS: .XXX ±
(.005),
(.015)
FRACTIONS: ± 1/64
ANGLE: ± 3 %
1
3
CCW
2
POTENTIOMETER
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
3851/3852/3856 – 3/4 ˝ Diameter Panel Control
Hardware
LOCKWASHER H-37-1
NUT H-38-1
6.6
(.26)
LOCKNUT H-38-3
9.53 +0/-0.38
(.375 +0/-.015)
2.36 ± 0.25
(.093 ± .01)
1/4-32 UNEF
12.07 ± 0.25
(.475 ± .01)
0.64 ± 0.05
(.025 ± .002)
LOCKWASHER H-37-2
4.57 ± 0.05
(.180 ± .002)
15 ° ± 1 °
7.75
(.305)
30 ° ± 5 °
TYP.
11 +0/-0.43
(.433 +0/-.017)
1/4-32
NEF-20
0.64
(.025)
7.92
(.312)
NUT H-38-2
9.58 ± 0.36
(.377 ± .014)
2.36 ± 0.25
(.093 ± .01)
1.02
(.040)
30 ° ± 5 °
3/8-32 NEF-2B
12.52 ± 0.36
(.493 ± .014)
0.56 ± 0.05
(.022 ± .002)
Date Code Description
YYWWM
30 ° ± 5 °
14.66 +0/-0.43
(.577 +0/-.017)
DIMENSIONS:
3.96
(.156)
MM
(INCHES)
LOCKNUT H-38-4
1.91
MIN.
(.075)
8.51 ± 0.05
(.335 ± .002)
18 ° ± 2 °
M = COUNTRY OF MANUFACTURE
(MEXICO)
3/8-32
NEF-2B
WW = WEEK NUMBER
YY = LAST TWO DIGITS OF YEAR
MANUFACTURED
1.02
(.040)
12.7
(.5)
1.14 ± 0.38
(.045 ± .015)
30 ° ± 5 ° TYP.
4.83
(.19)
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
3851/3852/3856 – 3/4 ˝ Diameter Panel Control
How To Order
3852
A
-
12
16
16
20
SHAFT TYPE
(FMS) & DIAMETER
3/8 ” (9.53 mm) L X 1/8 ” (3.18 mm) D
1/2 ” (12.7 mm) L x 1/4 ” (6.35 mm) D
1/2 ” (12.7 mm) L x 1/8 ” (3.18 mm) D
5/8 ” (15.88 mm) L X 1/4 ” (6.35 mm) D
28
7/8 ” (22.20 mm) L X 1/4 ” (6.35 mm) D
28
7/8 ” (22.20 mm) L X 1/8 ” (3.18 mm) D
28
2
-
103
A
AVAILABLE ONLY IN
MODELS
3851, 3852
3851, 3852
3851, 3852
3851, 3852
3851, 3852
3856
3851, 3852
3856
BUSHINGS
C
A
C, E
A, B
A, B
A
C, E
H
Consult factory for lengths not shown.
A
B
C
E
H
BUSHING
Plain 3/8 ” (9.53 mm) D x 3/8 ” (9.53 mm) L
Locking 3/8 ” (9.53 mm) D x 1/2 ” (12.7 mm) L
Plain 1/4 ” (6.35 mm) D x 1/4 ” (6.35 mm) L
Locking 1/4 ” (6.35 mm) D x 1/2 ” (12.7 mm) L
Plain 3/8 ” (9.53 mm) D x 3/8 ” (9.53 mm) L
APPLICABLE MODELS
3851, 3852, 3856
3851, 3852
3851, 3852
3851, 3852
3856 (3.18 mm D Shaft)
MODEL
3851 3/4 ” (19.05 mm) D Single-Turn C.P.
3852 3/4 ” (19.05 mm) D Single-Turn Cermet
3856 3/4 ” (19.05 mm) D 3-3/4-Turn Cermet
Boldface features are Bourns standard options.
All others are available with higher minimum order
quantities.
TERMINAL STYLE AND
SHAFT TYPE
1
2
3
5
6
7
Solder Lugs, Plain End
Solder Lugs, Slotted End
Solder Lugs, Flatted Shaft
PC Pins, Plain End
PC Pins, Slotted End
PC Pins, Flatted Shaft
L
RESISTANCE
CODE/VALUE
(IN OHMS)
Model 3851
(102)
1K
(252)
2.5 K
(502)
5K
(103)
10 K
(253)
25 K
(503)
50 K
(104)
100 K
(254)
250 K
(504)
500 K
(105)
1M
Models 3852/3856
(101)
100
(251)
250
(501)
500
(102)
1K
(252)
2.5 K
(502)
5K
(103)
10 K
(253)
25 K
(503)
50 K
(104)
100 K
(254)
250 K
(504)
500 K
(105)
1M
ELEMENT
TAPER/TOLERANCE
A
Linear ±10 %
B
Linear ±20 %
C
Audio CW ±10 %
D
Audio CW ±20 %
E
Linear ±10 %
F
Audio CCW ±10 %
G
Audio CCW ±20 %
H
Linear ±5 %
RoHS IDENTIFIER
L
Compliant
APPLICABLE
MODELS
3852, 3856
3851
3852, 3856
3851
3851
3852, 3856
3851
3852, 3856
Asia-Pacific: Tel: +886-2 2562-4117 • Email: asiacus@bourns.com
EMEA: Tel: +36 88 885 877 • Email: eurocus@bourns.com
The Americas: Tel: +1-951 781-5500 • Email: americus@bourns.com
www.bourns.com
REV. 10/20
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
Legal Disclaimer Notice
This legal disclaimer applies to purchasers and users of Bourns® products manufactured by or on behalf of Bourns, Inc. and
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Unless otherwise expressly indicated in writing, Bourns® products and data sheets relating thereto are subject to change
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