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Safety

Short chapter. Read all of it. Low-voltage electronics is a safe hobby because people respect the few things that bite.

Electricity

  • Mains (wall outlet) is off-limits. 120V/240V AC can kill you, and mistakes happen in milliseconds. Never open mains-powered equipment, never wire a mains plug, never "just" probe a live outlet as a beginner. This guide's circuits are all low-voltage DC for a reason.
  • Low voltage is forgiving, not harmless. A car battery or a big LiPo can source hundreds of amps into a short — molten wire, fire. Respect high-current sources even at 12V.
  • Capacitors hold charge. Big electrolytics (power supplies, especially old CRTs/microwaves — don't open those, ever) can bite after unplugging. Discharge through a resistor, not a screwdriver (the spark welds).

Heat and fumes

  • The iron is 350°C. It burns on contact, instantly. Always return it to the stand — never lay it on the bench. Assume every metal object near the work area is hot until proven otherwise.
  • Solder fumes: the visible wisp is mostly flux vapor — an irritant, not nerve gas, but don't breathe it deliberately. A small fan blowing across the work (not at your face) is enough.
  • Lead solder: wash your hands after soldering, don't eat at the bench, keep it from kids and pets. The danger is ingestion over time, not touching it. Lead-free exists if you prefer.

Eyes and hands

  • Safety glasses when clipping leads — cut wire ends fly fast and far. Regular glasses count.
  • Sharp things: component leads, craft knives for cutting traces, fiberglass PCB edges. Cut away from yourself; the knife will slip eventually.
  • Tweezers, not fingers, for holding small parts near the iron.

Batteries

  • Lithium (LiPo/Li-ion): puncture, crush, or overcharge = fire that's hard to put out. Charge on a non-flammable surface, never unattended; stop using puffy/damaged cells. Use a proper charger — not a random 5V supply.
  • Don't short batteries. A paperclip across a 9V gets hot enough to burn in seconds. Cap or tape terminals in the parts bin.

The mindset

None of this is meant to scare you off — millions solder safely. It's meant to make the precautions habits: glasses on, fan on, iron in the stand, hands washed. Five seconds of setup buys the whole hobby.

Next: Troubleshooting