Switches let you stop the flow of electricity or break a circuit.

Switches come in many varieties

• on (off), off (on)
• toggle, pushbutton
• latching, non-latching
• SPST, SPDT, DPST, DPDT etc…

When a switch is OPEN - current cannot pass through. When a switch is CLOSED current can pass through it.

Wiring a switch is slightly harder than you might think. The switch we are using makes a connection (circuit is closed) between two things when it is pressed. Which of the following schematics do you think is right?  Write down the one you think is correct and predict what value (0 or 1) the input will read in each schematic when the switch is open (button not pressed) and when the switch is closed (button pressed).