Electricity and power, without the maths

Three words come up constantly in electronics. You don't need the maths — you need the feel.

Think of electricity like water in a pipe:

• Voltage (volts, V) is the push — like water pressure. A 5 V supply pushes harder than a 3.3 V one.
• Current (amps, A, or milliamps, mA) is how much flows — like the flow rate through the pipe.
• Power (watts, W) is voltage × current — how much work is actually getting done.

Why it matters

Every component wants a particular voltage. A sensor might be a "5 V part"; a controller chip might be a "3.3 V part." Give it the voltage it expects and it's happy. Give it too much and you can destroy it (electronics people joke about letting out the "magic smoke").

Forge handles this matching for you — it won't hand a 3.3 V chip a 5 V supply. But knowing the vocabulary means you can read what Forge is doing and understand the choices it makes, instead of taking them on faith.

There are two ways to power a product, and the choice changes everything downstream.

Plugged in (wall or USB)

Steady 5 V, runs forever while it's connected, dead simple. The downside: it's tethered — it only works near a socket or a laptop.

On a battery (portable)

Free to move around, but two catches:

1. The voltage isn't a round number. A common lithium (Li-ion / LiPo) cell is 3.7 V "nominal" — really it drifts from about 4.2 V full down to 3.0 V empty. Meanwhile your parts want a clean 5 V or 3.3 V.
2. It has to be charged — safely. Lithium cells need proper charging and protection, or they misbehave.

So a battery product quietly needs a bit more: a small converter to turn the wobbly 3.7 V into a steady 5 V (a boost) or 3.3 V (a regulator), plus a charging + protection circuit.

The good news: in Forge's library these are ready-made blocks (a "3.7 V → 5 V boost," a "LiPo protection + charging" module). You don't design them — you just know that "portable" = battery + charging + a converter, and "plugged in" = simpler.