Chapter · Electricity
Powering the board
3.3 V against 5 V, and how much current the whole board actually draws.
- 14Logic levels, 3.3 V and 5 V9 minA digital wire does not carry a 1 or a 0. It carries a voltage, and the chip at the far end has an opinion about what counts. Those opinions differ between 3.3 V and 5 V parts, and the mismatch damages pins quietly rather than loudly.
- 15Power budget8 minBattery life is one number — the average current — and it is almost never set by the thing you think. Wi-Fi bursts are cheap. The power LED nobody removed is not.
Start at 14 and read down — the order is the order things get easier in. Or take the one with your part in it; every article stands on its own, and links back to whatever it needs.