1. Elementary Electronics for Switch Activities Hsin-yu Chiang

2. Learning Objectives Name basic switches with 80 % accuracy Construct a simple switch with 100 % accuracy Define terms used in switch construction with 100 % accuracy

3. Tools Needed Soldering iron Soldering iron Holder for soldering iron Holder for soldering iron Wire cutter Wire cutter Materials Solder Solder Speaker wire Speaker wire Copper wafer Copper wafer Microswitch Microswitch Batteries Batteries Radio or toys Radio or toys Wire stripper Wire stripper

4. Electricity Works in a Circle Never overpower devices ! Never overpower devices ! Do not built switches for items that run on alternative current(AC)! Stick to direct current (DC) Do not built switches for items that run on alternative current(AC)! Stick to direct current (DC) Open circuit Open circuit Closed circuit Closed circuit

5. Basic Switches Lever switch Roller-lever switch

6. Button switch Toggle switch Slide switch Paddle switch

7. Procedures: Cut a piece of standard wire Cut a piece of standard wire Split both ends of the wire down the middle Split both ends of the wire down the middle Remove about ¼” of the plastic covering from the tip of each of the four split ends of the wire, thereby exposing the wire strands Remove about ¼” of the plastic covering from the tip of each of the four split ends of the wire, thereby exposing the wire strands

8. The 3 spots are marked “NO” (normally opened); “NC” (Normally closed); and C (common) The 3 spots are marked “NO” (normally opened); “NC” (Normally closed); and C (common) Look carefully at your switch. Some types have 2 terminals, but the lever switches have 3 terminals. Look carefully at your switch. Some types have 2 terminals, but the lever switches have 3 terminals.

9. One stripped tip at the first end of the wire will be threaded through the hole marked “C” One stripped tip at the first end of the wire will be threaded through the hole marked “C” If you want the circuit to be closed when the switch is pressed, thread the other tip though the hole marked “NO” If you want the circuit to be closed when the switch is pressed, thread the other tip though the hole marked “NO” If you want the circuit to be opened when the switch is pressed, thread the other tip though the hole marked “NC” If you want the circuit to be opened when the switch is pressed, thread the other tip though the hole marked “NC”

10. Solder the wire ends in place Solder the wire ends in place Lightly touch the solder to the same point Lightly touch the solder to the same point Touch the tip of the hot soldering iron the the point of connection Touch the tip of the hot soldering iron the the point of connection Make sure the solder melts into a smooth puddle that will hold the wire ends in place Make sure the solder melts into a smooth puddle that will hold the wire ends in place Do not use too much solder Do not use too much solder Solder the wire ends in copper wafer Solder the wire ends in copper wafer Slip the ends of wire with copper wafer to the ends of batteries Slip the ends of wire with copper wafer to the ends of batteries

11. Handling of soldering iron Handling of soldering iron

12. Final Product: Battery Interrupter

13. Samples of some casings for switches: PVC-tube squeeze-switch Doorknob switch

14. If the device does not go on when you hit the switch…….. The main On/Off switch The main On/Off switch The batteries The batteries The plug The plug One of the wire ends may be disconnected One of the wire ends may be disconnected

15. If the device runs continuously when you no longer activating the switch…….. Stripped wires may be touching each other keeping the circuit closed Stripped wires may be touching each other keeping the circuit closed Trim the wires and re-solder Trim the wires and re-solder