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Switch Accuators


Actuator refers to the type of mechanical action required to activate a switch.  The following are examples of the most common type of mechanically activated switches (switches activated directly by the user.)        

Type of Actuator

Example

Toggle - A toggle switch has a lever protruding from the front.  Toggle switches tend to have a very positive feel and look to them.  They are designed so you can easily tell if the switch is on or off. 

SPST toggle switch, photograph © Rapid Electronics
Photograph © Rapid Electronics
used by permission

Pushbutton - A pushbutton switch has an actuator that sticks out of the front: push it in to actuate the switch.  Classically, push button switches are momentary action: they work as long as the button is pressed.   There is a type of pushbutton switch called a "push on - push off" switch.  To use this switch you press the button once to activate it and again to deactivate it.

Push-to-make switch, photograph © Rapid Electronics
Photograph © Rapid Electronics
used by permission

Slide - A slide switch has a slot on the face, with a nub that can be pushed from one side to the other. Slide switches tend to be inexpensive. The chief drawback of slide switches is that it is possible to push the nub partway, leaving your circuit in an indeterminate state: is it on, off, or part on and part off?  Slide switches are generally designed for mounting in panels and can be difficult to mount in something other than a thin meal or plastic panel.

DPDT slide switch, photograph © Rapid Electronics
Photographs © Rapid Electronics
used by permission

Rocker - A rocker switch has a pivot and an actuator that moves like a playground see-saw: you push one side down and the other side goes up; push the up side down and the other side goes up.  Rocker switches also tend to have a very positive feel to them and will generally make an audible click when pressed.

DPST rocker switch, photograph © Rapid Electronics
Photographs © Rapid Electronics
used by permission

Key switch

Key switches come in many different types.  The term refers to a switch that must be operated by a key.  Key switches can have multiple poles and positions.  Key switches can also be momentary.

Keyswitch, photograph © Rapid Electronics
Photographs © Rapid Electronics
used by permission

Micro Switch - A micro switch (sometimes called a roller switch) is a switch designed to switch on in response to small movements.  They usually come with rollers or levers to activate the switch.

Microswitch, photograph © Rapid Electronics
Photographs ©
Rapid Electronics
used by permission

Magnetic - A magnetic switch (also sometimes referred to as a reed switch) is a switch that is activated when a magnet is placed near it.  The switch contains two metal plates that the magnet causes to close (or open).  If you have a home security system then there are probably magnetic switches on your doors and windows.


click for larger picture

Tilt - A tilt switch (sometimes called a safety switch or mercury switch) is a switch that activates dependent on its physical orientation.  Typically they have a sealed container with one or more electrical contacts. The container is filled with mercury.  As the orientation of the switch changes the mercury either moves away from the contacts thus "opening" the switch or encloses the contacts thus "closing" the switch.   Most small electrical space heaters include some type of tilt switch to turn the power to the heater off should it be knocked over.

Tilt switch, photograph © Rapid Electronics

Photographs © Rapid Electronics
used by permission

 

Rotary - A rotary switch is actuated by twisting the protruding knob or shaft.  Although rotary switches can be simple, they are commonly employed in situations where the switch wants to have more than two settings.

Multi-way rotary switch

Multi-way rotary switch, photograph © Rapid Electronics

Photographs © Rapid Electronics
used by permission

Other Considerations on Actuators

 

Center Off double throw switch - Most double throw switches are generally always "ON" in one direction or the other.  Power is either being switched to one throw or the other.   There are versions of toggle and slide (and other type) switches that are center off switches.  These switches have a center position that is "off" where there is no connection to either throw.  The SPDT knife switch demonstrates a "center off" switch.  With the knife raised there is no connection being made to either throw.

Lighted Switch - Some pushbutton switches have a light built into the button that lights up when the switch is turned on.