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What is a Thumbwheel Switches?

2023-12-01 14:27:52

Thumbwheel Switches are setting switches that convert the numeric value by turning a disk shaped part where numbers are written, into binary, decimal or hexadecimal code, using the combination OF ON and OFF for multiple contact circuits, and then output the resultant code.



In the middle of the 20th century, with the advent of electronic devices and the first computers, there was an increasing need for a simple way to enter numerical data. It was necessary for many tasks, including setting parameters, programming and data entry.

Data entry was done using various mechanisms before thumbwheel switches. These included punch cards, toggles, rotary dials and patch panels. These methods were cumbersome and less precise or not suitable for quickly entering complex data.

Thumbwheel switches became more popular in the 1960s and 70s as a practical alternative. The thumbwheel switches combined the concept of rotary encoding with an intuitive interface that allowed users to manually enter numerical or alphanumeric value by rotating small wheels.



Thumbwheel Switches consist of parts rotary wheels, Contacts, Encoder Mechanism, etc. The following is a brief description of the components.


Rotary Wheels

 The thumbwheel switch is made up of these primary components. Each wheel represents either a digit (0-9), or an alphanumeric symbol.


Encoder Mechanism


The encoder mechanism on each wheel converts the rotational movement of the thumbwheel into electrical signals. This mechanism can include gears or contacts that translate the physical movement into electrical signals.


Contacts or Conductive Traces

Contacts or conductive tracks are embedded within or around the wheel and correspond to the characters or numbers on the wheel. These contacts or traces connect with the fixed contacts as the wheel rotates, creating circuits that represent the selected value electronic.


Housing and Mounting

The housing of thumbwheel switches provides protection and structural support. The housing can include mechanisms that ensure the smooth rotation of wheels and maintain their alignment.


Output Connections

Output connections are used to transmit the electrical signals generated by thumbwheel switches. These connections enable the switch to interface the electronic circuitry with the device or system that utilizes the input data.


Display Window

Some thumbwheel switches feature a display panel or window through which the user can see the selected characters or digits.


End caps

The Switch Units have End Caps on each end. Installing the Switch Unit is as simple as pushing the mechanism of the End Caps in the hole.






The displayed characters or digits are usually visible through a display or window, which makes it easier for the user to verify and read their input data.


They are generally durable and reliable because they are mechanical, since they do not rely on complicated electronic components.

Simple Interface

These systems provide an easy-to-use interface to input data without the need of complex instructions or user manuals.



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