Electrical safety for makers
Rules that protect you and your boards.
- Unplug power before changing wiring.
- Never short 5V or 3.3V to GND.
- Every LED gets a resistor; every motor gets a driver.
- Never put 5 V on an ESP32 GPIO.
- Battery packs (especially Li-ion) can get hot — don't short them, puncture them or leave them charging unattended.
- Mains voltage (220 V in Bangladesh) can kill. Students should never work on the high-voltage side of a relay; ask a qualified adult.
The simulator flags many mistakes, but it is a simplified model. A circuit that works here should still be checked carefully before you power real hardware.