Arduino · Module 9 of 10

Electronics safety and best practices

Build circuits safely and reliably.

📖 Key ideas

Never connect Arduino directly to 230V mains; use certified relay modules and supervision.
Check polarity and voltage before powering.
Use common ground between modules.
Limit current per pin (~20 mA recommended).
Organise wiring and label connections.

💡 Real-life example: Electronics safety is kitchen safety: respect the fire (current) and keep things tidy.

Common groundShared reference between circuits

PolarityCorrect + and − orientation

Current limitMaximum safe current

Short circuitUnintended low-resistance path