One tiny interruption.
Picture a battery connected to a lamp in a complete loop. Now imagine a small gate along one wire. When the gate touches both sides, the path is complete. When it lifts away, the path is open.
Lesson 2 of 3
Think like a switch.
A switch doesn’t make electricity. It gives you a way to control the path.
Design a secret signal.
Draw a battery, a lamp, and a switch in a single loop. Label the switch open. Draw a second version with the switch closed.
Invent a signal using light: one short flash for “hello,” two for “ready,” or your own pattern. Write down when your switch needs to open and close.
What if there were two?
Add another switch along the same loop. Predict whether the lamp lights when only one switch is closed. Trace the entire path to check your answer.
Both switches must close to complete this single path. Where might that be useful?
Try it: two switches.
Flip A and B. Then change how they are wired, and check your prediction against the table.
The drawing shows two switches one after another (series). Switch A is closed and switch B is open, so the path has a gap and the lamp is off. In series both switches must close; side by side (parallel), either one can complete a path.
Switches
Pressed means closed.
Wiring
Series: both switches must be closed. Lamp is off.
Logic Series works like AND: the lamp lights only when A and B are closed.Parallel works like OR: the lamp lights when A or B (or both) is closed.
| A S1 | B S2 | Lamp DS1 |
|---|---|---|
| open | open | off |
| open | closed | offon |
| closed | open | offon |
| closed | closed | on |