You already know a bulb only lights up when its circuit is complete. The electricity that moves round that whole loop is called current. A switch is a tiny gap in the wire that you control. Close the gap and the circuit is whole. Open the gap and the circuit breaks.
Every wall switch in your home hides this same gap. Flip it up and the circuit closes, so the light turns on. Flip it down and the circuit opens, so the light turns off.
You never touch bare wires to turn something on or off. The switch does that job safely, whether it is a lamp, a buzzer, or a doorbell button.
A closed switch completes the circuit and an open switch breaks it. That gap is how switches at home control lamps and buzzers.
Last time you hunted a loop for gaps, because one gap anywhere keeps the bulb dark. The class torch lights now, but the only way to turn it off is to pull a wire off the cell.
Zoe wants a proper on and off. What does a switch add to the torch?
Open and close the switch, and watch the gap you control do its job.
اول این‌ها را یاد بگیر
این موضوع راه این‌ها را باز می‌کند
شغل‌هایی که بر این مهارت تکیه دارند. دنبال کردن یکی برای دیدن همهٔ چیزهایی که بر آن‌ها بنا شده است.
۸ سؤال پشت این درس منتظرند، هر کدام با پاسخ توضیح‌داده‌شده. هر پاسخ آسمان را پر می‌کند: ستاره‌ها هنگام یادگیری روشن می‌شوند و وقتی زمان برگشتن است کمرنگ می‌شوند.