1. Rotary Switch Basics “Using Rotary Switches in Your Design”
Welcome to Electroswitch’s Rotary Switch training. In this module we will review rotary switch design considerations, commonly asked questions, and the features of our rotary switches.

2. Electroswitch Rotary Switches
Electroswitch offers many varieties of rotary switches for different application requirements. Electroswitch has acquired rotary switch lines from Stackpole, Shallcross, ASM, CRL / Centralab and Oak Grigsby. This gives Electroswitch years of manufacturing and design experience with rotary switches.
Electroswitch offers many varieties of rotary switches for different application requirements. Electroswitch has acquired rotary switch lines from Stackpole, Shallcross, ASM, CRL / Centralab and Oak Grigsby.

3. Rotary Switch Design Considerations & Common Specifications
How many poles?
Open or enclosed Frame switch?
Changing Torque or Actuation Feel?
Contact Material Advantages?
Sealing Requirements?
Size requirements or limitations?
How many positions?
Mounting Style –
PCB or panel mount?
There are several design considerations when picking a rotary switch. They include: How many poles?
Open or enclosed Frame switch? Changing Torque or Actuation Feel? Contact Material Advantages? Are there sealing requirements? Size requirements or limitations? How many positions? Mounting Style either PCB or panel mount?

4. What is a Pole?
A pole is the input or common terminal. It is an electrically isolated switching circuit.
Rotating Contact
Output Terminals
Common Pole
A pole is the input or common terminal. It is an electrically isolated switching circuit. The rotating contact will channel the signal from the pole to the output terminals. The number of output terminals required determines how many positions a switch will have.
The rotating contact will channel the signal from the pole to the output terminals. The number of output terminals required determines how many positions a switch will have.

5. What is a Section?
A section is also referred to as the deck, wafer or module.
sections
A section is also referred to as the deck, wafer or module. Sections are made up of the common and position terminals of the switch. Switches can be made of several sections to obtain multiple poles.
Sections are made up of the common and position terminals of the switch. Switches can be made of several sections to obtain multiple poles.

6. Poles vs Section
You can also have more than 1 pole on a section. Common specifications list total poles, poles per section, active positions, and number of sections. Multiple poles per section will limit the number of available active positions.

7. What is the difference between enclosed and open frame?
In open frame switches the moving parts are visible. The enclosed frame switches the parts are not visible.
Open Frame switches have more flexibility on custom contact configurations
Open Frame have a bifurcated wiping or “self cleaning” contact system ensuring reliable operation.
Open Frame switches can have sections sold separately
Enclosed Frame offers more protection from dust and contamination
Enclosed frame switches are generally less expensive
Enclosed frame switches are generally more compact
Rotary switch general construction includes either open or enclosed frame. In open frame switches the moving parts are clearly visible. In enclosed frame switches the parts are not visible. The design considerations for each are: Open Frame switches offer more flexibility for contact configurations. Open Frame have a bifurcated wiping or self cleaning contact system ensuring reliable operation. Open frame switches can have sections sold separately.
Enclosed Frame offers more protection from dust and contamination. Enclosed frame switches are generally less expensive. Enclosed switches are generally more compact.

8. Can you change the "Feel" or Torque of the switch?
Yes. Changing the spring or number of springs in many switches will create a lighter or heavier detent actuation “feel”.
spring
Can you change the "Feel" or Torque of the switch? Yes. Changing the spring or number of springs in many switches will create a lighter or heavier actuation “feel”. This is done during the manufacturing process at Electroswitch.
This is done during the manufacturing process at Electroswitch.

9. When Should You Specify Gold Contacts?
Gold plated contacts should be used when your product needs a longer shelf life.
Also, if the switch will not be actuated for a long period of time after installation you may want gold contacts.
A common question is when should gold contacts be specified on a switch. Gold plated contacts should be used when your product needs a longer shelf life. Also, if the switch will not be actuated for a long period of time after installation you may want gold contacts.

10. What is the difference between Current Carrying Capacity & Current / Voltage Rating?
Current carrying capacity, measured in amps, is the maximum load that a switch will carry with the contacts in a closed position.
Current / voltage rating is the tested amperage and voltage capacity when switching contact positions under load (with current). An electrical arc occurs when switching between positions under load. Over a period of time, this arc may cause contact wear.
A switch with the contacts closed has no arc, and the carrying capacity is higher.
Electrical specifications include Current Carrying Capacity & Current and Voltage Rating. Current carrying capacity, measured in amps, is the maximum load that a switch will carry with the contacts in a closed position.
Current / voltage rating is the tested amperage and voltage capacity when switching contact positions under load. An electrical arc occurs when switching between positions under load. Over a period of time, this arc may cause contact wear.
A switch with the contacts closed has no arc, and the carrying capacity is higher.

11. What is the difference between Shorting & Non-shorting contacts?
Non-shorting contacts break before make
(narrower contact)
Shorting contacts make before break
(wider contact)
Electroswitch rotary switches are available with either non-shorting or shorting contacts. In a non-shorting, or break before make switch, the moving contact will break connection with the previous output terminal before making contact with the next output terminal. The moving contact has a narrower cut to achieve this. Non-shorting are the most common type contacts requested.
In a shorting, or make before break switch, the moving contact will make connection with the next output terminals before breaking with the previous output terminal. The moving contact will have a wider cut to achieve this. This may be required in attenuator type applications.

12. Different Stop Types
A stop limits the rotation of the switch to the desired number of positions.
Fixed Stop
Stops are built into the switch at the factory
Better for volume production requirements so customer does not have to adjust each switch
These stops are not changeable by the customer
Adjustable Stop
Stop type where customer can adjust switch to desired number of positions
Standard switches are supplied with adjustable stops preset at 2 positions
Good Choice for low volume requirements
Continuous Rotation
Switch with no stops
There are different stop types on rotary switches. A stop limits the rotation of the switch to the desired number of positions.
A Fixed Stop are stops has stops that are built into the switch at the factory. These are better for volume production requirements so customer does not have to adjust each switch. These are not changeable by the customer.
An Adjustable Stop offers the customer the flexibility to adjust a switch to the desired number of positions. Electroswitch standard switches are supplied with adjustable stops preset at 2 positions. These are a good choice for low volume requirements.
Continuous Rotation is a switch with no stops.

13. Adjustable Stop Mechanisms
Electroswitch rotary switches have different types of adjustable stops.

14. Can Electroswitch rotary switches be water resistant sealed?
Yes. Most Switch series offer a shaft and panel seal option. This allows the switch to be front panel sealed.
Can Electroswitch rotary switches be water resistant sealed? Yes. Most Switch series offer a shaft and panel seal option. This allows the switch to be front panel sealed from water intrusion. In addition our C series switches have the option to be completely sealed to meet an IP67 or submersion rating.
In addition, our C series switches have the option to be completely sealed to meet an IP67 (submersion) rating.

15. Applications Test and Measurement Pro and High end Audio
Military and Aerospace
Construction and Agricultural Equipment
Medical and Diagnostic Equipment
Transportation and Off Road Vehicles
Military and Commercial Communication
Rotary switches can be used in many applications. A rotary switch offers an easy way to switch more combinations than what is offered by other switches. It also offers the user a definite tactile feedback for position location. Rotary switches are generally more robust than other types of switches or potentiometers. Typical markets of Electroswitch customers include: Test and Measurement, Pro and High End Audio, Military and Aerospace, Construction and Agricultural Equipment, Medical and Diagnostic Equipment, Transportation and Off Road Vehicles, and Military and Commercial Communication
Rotary switches can be used in many applications. A rotary switch offers an easy way to switch more combinations than what is offered by other switches. It also offers the user a definite tactile feedback for position location. Rotary switches are generally more robust than other types of switches or potentiometers.

16. Rotary Switch Features Choosing the Right Switch for Your Design
The Electroswitch C series is an ideal choice for enclosed switch requirements. The C series is an economical option for lower current rotary switch needs. It is ideal for requirements that need a low profile compact switch. The C series has many available options including BCD or binary coded decimal outputs, water resistant sealing, push to turn and dual concentric shaft designs.
Many available options
Sealing to Meet IP67
The Electroswitch C series is an ideal choice for enclosed switch requirements. The C series is an economical option for lower current rotary switch needs. It is ideal for requirements that need a low profile compact switch. The C series has many available options including BCD or binary coded decimal outputs, water resistant sealing, push to turn and dual concentric shaft designs.

17. Enclosed TO5 Series Low Cost Smallest Switch, Only 362” in diameter
Options include a boot seal which prohibits
contamination of contacts during cleaning.
The Electroswitch T05 series offers a subminiature size at economical prices. Only .362” in diameter, this series has definite detent switching for applications with limited space allowances.

18. Rotary Switch Features Choosing the Right Switch for Your Design
The Electroswitch D series is the ideal choice for open frame switch requirements. This series has lots of design flexibility. The D series has many available options including water resistant sealing and dual concentric shaft options. The Electroswitch D1, D3 and D4 were originally designed to meet Mil Spec requirements.
Many available options
D1, D3 and D4 made to Mil Spec
The Electroswitch D series is the ideal choice for open frame switch requirements. This series has lots of design flexibility. The D series has many available options including water resistant sealing and dual concentric shaft options. The Electroswitch D1, D3 and D4 were originally designed to meet Mil Spec requirements.

19. Rotary Switch Features Choosing the Right Switch for Your Design
Unique Index Angles
Electroswitch has recently added several open frame series. These switches have unique features that include; Unidex housing, T-Slug terminals, tri-concentric shafts, and uncommon index angles. Several of the series also meet Mil spec requirements and have water resistant sealing options.
T-Slug Terminals
and
Tri Concentric Shafts
Electroswitch has recently added several open frame series. These switches have unique features that include; Unidex housing, T-Slug terminals, tri-concentric shafts, and uncommon index angles. Several of the series also meet Mil spec requirements and have water resistant sealing options.

20. Unidex Housing (A and F series)
Utilizing dual ball detent indexing on a rugged star wheel. This detent offers 100,000 cycles of mechanical life, with the torque remaining constant and crisp throughout the life of the switch.
Unidex Housing
The Electroswitch unidex housing utilizes a dual ball detent indexing on a rugged star wheel. This feature offers 100,000 cycles of mechanical life, with the torque remaining constant and crisp throughout the life of the switch.

21. “T” Slug Terminals (SK, 7M & 4M Series)
Wedgelock method of clip assembly
Stronger, Longer Life Switch
Patented "T" slug design eliminates rotation and twisting of contacts
Stator
The Electroswitch Wedgelock method of clip assembly, called "T" slug uses a flat strip of metal to securely fasten the clips to the stator. This method of assembly is a patented process and is used on the SK and 4M rotary switches. Because the flat strip of metal is "wedged" into the clip slot, the clip experiences almost no loosening. The unique shape of the "T" slug design eliminates rotation and twisting of contacts thus assuring maintenance of accurate timing throughout the life of the switch.
Electroswitch “T” Slug Terminals for added strength

22. Tri-Concentric Shafts For Multiple Functions (7M, LK and RK Series)
This assembly may consist of three switches in one frame or two switches & a potentiometer within the same frame limitations as a single shaft switch
The Electroswitch 7M, LK and RK series have the capability of being made with Tri-concentric shafts. This assembly may consist of three switches in one frame or two switches & a potentiometer within the same frame limitations as a single shaft switch.

23. Rotary Switch Features Choosing the Right Switch for Your Design
Standard Switches for:
Spring-Return,
High Current,
24 Position PC mount
The Electroswitch E series has standard options for special requirements. The E5 series is designed to meet the needs of a 24 position pc mount switch. The E3 series is a standard spring-return rotary switch. The E4 series has a current rating to switch 11 28VDC.
The Electroswitch E series has standard options for special requirements. The E5 series is designed to meet the needs of a 24 position pc mount switch. The E3 series is a standard spring-return rotary switch. The E4 series has a current rating to switch 11 28VDC.

24. Rotary Switch Features Choosing the Right Switch for Your Design
M6 and M7 can go up to 32 and 48 positions
The Electroswitch M series was originally designed to meet Mil Spec requirements. These switches are used in a variety of military, avionic and industrial applications. The M6 and M7 can go up to 32 and 48 positions.
The Electroswitch M series were originally designed to meet Mil Spec requirements. These switches are used in a variety of military, avionic and industrial applications. The M6 and M7 have the capability to go up to 32 and 48 positions.

25. Contact Digi-Key Design Support services:
Value-Added Options
Special readouts (BDC or other)
Made Specific to Drawing
Special Testing / Ratings Required
Overmolding
Key Lock
Cable Harness
Sealing (to IP67)
Special Grease (Temp or Life)
Knurled Shaft
Push to Turn Shaft
Dual Concentric Shafts
Electroswitch offers full service design and application engineering, an in house UL certified test lab, in house tool design and fabrication, vertical integration, and benchmark sample and production lead-times. It is easy for Electroswitch to customize and offer value added requirements to our products. Value added options include cable harness and wire lead assemblies, custom labeling, marking and overmolding.
Contact Digi-Key Design Support services: