Transcript Switches

Switches
• A switch allows you to “make” or “break”
the connection between two or more
points in a circuit.
• Pole – the moving contact(s)
• Throw – the non-moving contact(s)
• Switches are identified by the number of
poles and the number of throws
Switch Application
Switch Definitions
One moving contact
One non-moving contact
Single-Pole
Single throw
SPST – Single-Pole, Single-Throw switch
(On-Off Switch)
Toggle Switch
• Activate by pushing
against a lever arm
Push-Button Switches
• Activate the switch by pushing a button
• Two types of Push-Button Switches
• Normally-closed (NC)
– When the button is NOT pushed, the contact
is closed
• Normally-open (NO)
– When the button is NOT pushed, the contact
is open
Normally-Closed (NC)
Normally-Open (NO)
Reference Material
• Section 2.8, pp. 65-69 in your textbook.