RTC
www.vishay.com
Vishay Sfernice
Wirewound Rheostats and Potentiometers Graded Windings,
Ganged Assemblies
FEATURES
• Duo, trio or quattro configurations
RHEOSTATS AND POTENTIOMETERS WITH
GRADED WINDING: RTS
current
--------------------------------- exceeds 2, a graded unit may
When the ration max.
min. current
min. current enable a smaller sized unit to be used than an
equivalent linear law unit for the same maximum current.
Graded windings can also avoid the use of twin units.
Linear relationships are achievable between the variable
parameters being controlled and the rheostat command
shaft.
DATA REQUIRED TO DEFINE A UNIT
a: Ohmic value of the current load in series with the rheostat
b: Supply voltage of the rheostat + series load
All RT size rheostats are available with graded windings
except the RT12 size. The resistive wire is protected
by a specially Vishay Sfernice formulated enamel.
Mechanical and environmental characteristics are identical
to the RT series.
c: Ohmic value of rheostat
d: Maximum current when the rheostat is in short circuit
position
e: Current when the rheostat is set to maximum ohmic
value
f: Resistance variation law as a function of mechanical
travel
GANGED ASSEMBLIES
Rheostats may be ganged mechanically in the following
styles:
2 ganged units RTC DUO
3 ganged units RTC TRIO
4 ganged units RTC QUATTRO
To define a graded winding unit a, b and c; or c, d and e or
g has to be established.
The RT12 unit is not suitable for ganged assembly.
APPLICATION EXAMPLES
- Similar sized units, where the ohmic values may be
different
Potentiometer mode
The following data has to be established:
Ganged assemblies may comprise:
- Various sized units where the unit at the top end of the
command shaft can be of smaller size
- Potentiometer supply voltage U
- Ohmic value of the controlled current load Z
COMMAND SYSTEM
Note
• If the power to be controlled is small, a linear, variation
• All units with common command: Code CU
Shaft locking devices as an option: Code DBA (factory
assembled)
law rheostat can be used


Ohmic value: R = Z--- and I =
5
2
U
------Z
;
in such case the output current is
6U
I = ------Z
Control of lamps
The parameters to be established are:
- Light flux variation required:
Linear from 100 % to 1 %
log variation from 100 % to 4 %
or from 100 % to 20 %
- Lamp supply voltage

• Concentric shafts: Code CC
Available for double ganged units only: RTC DUO
The shaft locking device and double mini switch cannot be
fitted to concentric shaft
• Command knobs as an option:
Code JF for standard shaft, code JFP - FSP for concentric
shafts
SPECIAL FEATURES
For any special features such as graded windings,
centertappings, etc. We would be pleased to receive the
details of your particular requirements.
- Lamp power range
Revision: 08-Aug-13
Document Number: 50031
1
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
RTC
www.vishay.com
Vishay Sfernice
FEATURES
Mechanical, electrical, and environmental features are
similar to the RT series document numbers, 50024, 50025,
50026, 50027, 50028, 50029, 50030
DIMENSIONS in millimeters
Connection
K
DIMENSIONS
F
SERIES TYPE A
H
G
RTC
Duo
TRIO
C
MRT
E
F
G
H
J
-
19
23
30
81 3.5
30
38
30
92 4.5
25
52 34.5 30
55
25
63
46
41
-
100
25
75
58
53
-
42.5 54.5 30 110 M5
230
50
97
78
78
-
71.5 83
40 170
7
500
50 128 110 109
-
71.5 83
40 170
7
25
52 86.5 30
52
19
23
30
81 3.5
55
25
63
109
41
63
30
38
30
92 4.5
100
25
75
133
53
75 42.5 54.5 30 110 M5
230
50
97
175
78
97 71.5 83
40 170
7
500
50 128 238 109 128 71.5 83
40 170
7
25
25
55
RTC
100
Quattro
230
25
63
172
25
75
208
50
97
272
78
97 71.5 83
40 170
7
50 128 366 109 128 71.5 83
40 170
7
52 138.5 30
52
19
23
30
81 3.5
41
63
30
38
30
92 4.5
53
75 42.5 54.5 30 110 M5
Notes
• RTC Duo 2 ganged units
• RTC Trio 3 ganged units
• RTC Quattro 4 ganged units
5
C
Ø
H
D
25
500
QUARTO
C
25
RTC
Trio
FRT
B
C MRT
PANEL CUT-OUT
E
PANEL
CUT-OUT
Type
L
M
ØN
CRT
B
DUO - TRIO - QUATTRO
25
55
23
3.5
55
66
20
4.5
100
62
20
M5
230
110
24
7
500
110
24
7
D
CONCENTRIC SHAFT
Mounting
Plane
A + 2
SERIES
J
P
RTC
Duo
PANEL CUT-OUT
(1)
TYPE
ØP
ØQ
R
S
25
55
100
230
500
6
6
6
10
10
3.5
3.5
3.5
5
5
20
21
21
25
25
31
38
45
45
45
Note
(1) 2 ganged units only
CONCENTRIC SHAFT
S
Ø 12
M
ØN
ØQ
ØP
L
R
Revision: 08-Aug-13
Document Number: 50031
2
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
RTC
www.vishay.com
Vishay Sfernice
ELECTRICAL DIAGRAM (typical use)
Z
Z
G
G
Z
G
Single
rheostat
connected
Single
potentiometer
connected
G
Double rheostat parallel
connected, load in series
Triple rheostat series connected
Double potentiometer series
connected, load in parallel
Z
Z
G
G
Z
G
Z
Triple rheostat connected, used for
three phase current regulator
Double potentiometer parallel
connected, load in series
Z
G
Z
Double bridge
G
Double potentiometer parallel
connected, load in parallel
G
Z
Triple potentiometer connected, used
for three phase current regulator
MARKING
Graded winding units: RTS
Vishay Sfernice trademark, series, style, number of graded, windings, ohmic value (in  or k), tolerance (in %), maximum
current (in A), manufacturing date
Ganged units: RTC: Duo, Trio, Quattro
Vishay Sfernice trademark, series, style, the relative position of each unit in the assembly.
CRT 1st unit (command knob end),
MRT 2nd and/or 3rd unit,
FRT last unit,
ohmic value (in  or k), tolerance (in %), maximum current (in A), manufacturing date
Revision: 08-Aug-13
Document Number: 50031
3
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
RTC
www.vishay.com
Vishay Sfernice
ORDERING INFORMATION
RTC
DUO
25
CU
2x7
10 %
e
SERIES
TYPE
STYLE
COMMAND
SHAFT
OHMIC VALUE
TOLERANCE
LEAD (Pb)-FREE
Common Shaft
CU
Trio
Quattro
Concentric Shaft
CC
GLOBAL PART NUMBER INFORMATION
T
GLOBAL
MODEL
DRT (duo)
TRT (trio)
QRT (quattro)
Revision: 08-Aug-13
R
T
1
0
0
C
U
4
7
0
0
K
SIZE
COMMAND SHAFT
OHMIC VALUE
TOLERANCE
PACKAGING
SPECIAL
012
025
055
100
230
500
CU = Common shaft
CC = Concentric shaft
The first three digits are
significant figures and the
last digit specifies the
number of zeros to follow.
R designates decimal point.
2002 = 20 k
4700 = 470 
22R0 = 22 
1000 = 100 
K = 10 %
B = Box BO1
As applicable
Ex.: DXxx
Document Number: 50031
4
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
Legal Disclaimer Notice
www.vishay.com
Vishay
Disclaimer

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RELIABILITY, FUNCTION OR DESIGN OR OTHERWISE.
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“Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained in any datasheet or in any other
disclosure relating to any product.
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the continuing production of any product. To the maximum extent permitted by applicable law, Vishay disclaims (i) any and all
liability arising out of the application or use of any product, (ii) any and all liability, including without limitation special,
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Statements regarding the suitability of products for certain types of applications are based on Vishay’s knowledge of
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statements about the suitability of products for a particular application. It is the customer’s responsibility to validate that a
particular product with the properties described in the product specification is suitable for use in a particular application.
Parameters provided in datasheets and / or specifications may vary in different applications and performance may vary over
time. All operating parameters, including typical parameters, must be validated for each customer application by the customer’s
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including but not limited to the warranty expressed therein.
Except as expressly indicated in writing, Vishay products are not designed for use in medical, life-saving, or life-sustaining
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Please contact authorized Vishay personnel to obtain written terms and conditions regarding products designed for
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Revision: 13-Jun-16
1
Document Number: 91000