Working safely
A short list of rules that keep your circuit, your battery, and you all happy.
Read first: A complete loop
Most beginner circuits are very safe. A 9 V battery cannot push enough current through your skin to hurt you. But a few simple rules keep everything pleasant.
The four rules
1. Never wire the battery + straight to the battery − with just a wire. That is a short circuit. The wire gets hot, the battery dies fast, and in real life it can melt insulation.
2. Always pair every LED with a resistor. Without it, the LED gulps down too much current and burns out in a flash.
3. Do not poke metal into wall sockets. Ever. The voltage is 120 or 230 volts and will hurt you. Wall power is not for breadboard projects.
4. Get a grown-up if you're unsure. Even professional engineers ask each other questions. Asking is how you learn faster.
Now you understand…
- Never wire battery + straight to − with no part in between.
- Every LED needs a resistor. No exceptions.
- Wall sockets are not for breadboard projects.
- When in doubt, ask. Even pros do.