Working Mechanism Of Rotary Switches

When one needs to control different circuits or has to select many different values for one circuit with a single switch, rotary switches are ideal to use. These switches rotate in a circular manner, thereby turning the different circuits as per their position to make them work.

Initially rotary switches were only used in television and served the purpose of selecting different channels. But today with the development in digital technology, these switches are used even in the inset applications of industrial controls, CB radios, electronic instruments and some aircrafts. The article highlights how a rotary switch works.

Function Of Spindle: The spindle in a rotary switch rotates continuously. The current runs to get distributed through several different rotors attached on the spindle. Each rotor has an arm that moves outwards and is in contact with the directing terminal when the switch comes in the perfect position. A rotary switch has a capability of attaching almost a dozen possible positions, each one of them attached to a particular circuit.

Rotary Switch

Rotary Switch

The Switch Control: To start a specific circuit with rotary switches, it has to be in perfect position. If the switch rotor has an excessive movement, it will lead to the application being shut down. To avoid such accidents, rotary switches use a mechanism in which the switch sticks to one position and stays in the same place until it is turned across with a greater force. This detent mechanism has a wheel with grooves cut into, which is attached to the rotor. The ball bearing has a spring steel that presses against the wheel to create static force. Once it is rotated, the switch turns to the next position. If there are more than 2 positions in the application, a three deck rotary switch is used.

Modern day rotary switches are user configurable and can be set according to the number of positions. Usually a special toothed washer is used so that the tooth can be used to block the number of slots not needed for any particular application. Thus, rotary switches show much higher capabilities in comparison to simple ones.


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