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 non-moving contactOne moving contact Single-PoleSingle 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 in your textbook.