1. 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

2. Switch Application

3. Switch Definitions One non-moving contactOne moving contact Single-PoleSingle throw SPST – Single-Pole, Single-Throw switch (On-Off Switch)

4. Toggle Switch Activate by pushing against a lever arm

5. 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

6. Normally-Closed (NC) Normally-Open (NO)

7. Reference Material Section 2.8, pp. 65-69 in your textbook.