Rotary Switch BasicsUsing Rotary Switches in Your Design

Rotary Switch BasicsRotary Switch Basics ““Using Rotary Switches in Your Using Rotary Switches in Your

Design”Design”

Electroswitch Rotary SwitchesElectroswitch 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.

Rotary Switch Design Considerations & Rotary Switch Design Considerations & Common SpecificationsCommon 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?

What is a Pole?What is a Pole?A pole is the input or common terminal. It is an electrically

isolated switching circuit.

Common Pole

Output Terminals

Rotating Contact

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.

What is a Section?What is a Section?

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

Poles vs SectionPoles vs Section

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

What is the difference between What is the difference between enclosed and open frame?enclosed and open frame?

Can you change the "Feel" or Torque of the switch?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”.

This is done during the manufacturing process at Electroswitch.

spring

When Should You Specify Gold When Should You Specify Gold Contacts?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.

What is the difference between Current What is the difference between Current Carrying Capacity & Current / Voltage Rating?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.

What is the difference between Shorting & What is the difference between Shorting & Non-shorting contacts?Non-shorting contacts?

Non-shorting contacts break before make(narrower contact)

Shorting contacts make before break(wider contact)

Different Stop TypesA 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

Adjustable Stop Mechanisms

Can Electroswitch rotary switches Can Electroswitch rotary switches be water resistant sealed?be water resistant sealed?

Yes. Most Switch series offer a shaft and panel seal option. This allows the switch to be front panel sealed.

In addition, our C series switches have the option to be completely sealed to meet an IP67 (submersion) rating.

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.

Rotary Switch FeaturesRotary Switch FeaturesChoosing the Right Switch for Your DesignChoosing 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

• Low Cost • Smallest Switch, Only 362” in diameter • Options include a boot seal which prohibits contamination of contacts during cleaning.

Enclosed TO5 SeriesEnclosed TO5 Series


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

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.

Unique Index Angles

T-Slug Terminals

and

Tri Concentric Shafts


Unidex HousingUnidex Housing (A and F series)(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

““T” Slug TerminalsT” Slug Terminals(SK, 7M & 4M Series)(SK, 7M & 4M Series)

• Wedgelock method of clip assembly• Stronger, Longer Life Switch • Patented "T" slug design eliminates rotation and

twisting of contacts

Electroswitch Electroswitch “T” Slug “T” Slug

Terminals for Terminals for added strengthadded strength

StatorStator

Tri-Concentric Shafts For Multiple FunctionsTri-Concentric Shafts For Multiple Functions(7M, LK and RK Series)(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 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 Amps @ 28VDC.

Standard Switches for:

Spring-Return,

High Current,

24 Position PC mount


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.

M6 and M7 can go up

to 32 and 48 positions

•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

Value-Added OptionsValue-Added Options

Contact Digi-Key Design Support services:http://dkc1.digikey.com/us/en/mkt/VBD/designsupport.html

http://dkc1.digikey.com/us/en/mkt/VBD/designsupport.html

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Rotary Switch BasicsUsing Rotary Switches in Your Design