Reading a live sheet

Voltage or current, the halo, the amber dots, the cyan wave — every visual signal a running circuit gives you, and what it is teaching.

A running sheet is telling you two different things at once, and most confusion comes from reading them as one:

Voltage — this conductor is at potential.
Current — charge is actually circulating through it.

A wire can have the first without the second. That is what an open circuit is. UnifCAD never merges the two signals.

Two visual styles

The Zap button in the toolbar switches between them.

Style	Speaks through	Plan
Classic colours	colour	included in Free — the default
Animated flow	motion	Pro

Each style deliberately uses one channel only. A flow-style conductor keeps its drawing colour precisely so the amber dots stay readable on top of it.

Classic colours

The conductor switches to its lit colour, and grows a halo when current flows.

What you see	What it means
Brighter colour	the conductor is at voltage
A halo around it	current is flowing through it
A thick outline	it is selected — selection works during simulation too

A wire drawn in plain ink adopts the colour of its nature when it lights up, so a monochrome drawing gives you a full-colour simulation. A wire already drawn in a colour code keeps its identity and simply brightens. See wire colours.

Animated flow

Amber dots — electrons — travel inside the conductor, thinner than the wire itself, because that is where they are: in the copper.

The dot is voltage, the movement is current

At rest the dots are still and dimmed: there is potential, nothing is circulating. When they move, current is flowing. Nothing trembles — with the loop open there is no net movement to show, and a coherent tremble would suggest a back-and-forth that does not exist.

Alternating current sways; direct current drifts

On AC, the dots sway in place. Electrons never lap an AC circuit — over a cycle their net travel is zero. Three-phase gets one clock per phase: L2 lags L1 by 120°, L3 by 240°, which is the rotating field the motor actually turns on.
The sway follows the source frequency. At 60 Hz the dots move faster and travel a shorter distance than at 50 Hz — and the product of the two, which is the current, is the same. That is the lesson hiding in the animation.
In a line-and-neutral loop the two conductors move in opposite directions at every instant. They are the out and the return of one circuit; both "leaving" at once would mean current entering the load through both terminals.
On DC, the dots drift steadily: out of the negative rail, across the load, back to the positive one. One circulating loop, not two streams converging.
The protective conductor never animates. No current flows through a healthy PE.

Conventional current or electron flow

The Current direction toggle (⇄, shown when the flow style is on) lets you choose which convention the dots obey:

Conventional — the engineering standard, from + to −.
Electron flow — the real movement of charge in the metal, from − to +.

Both are correct. Conventional current was defined before the electron was discovered, and the mathematics is identical either way; only the direction of the dots changes. Pick the one your students — or your habits — expect.

The cyan wave at switch-on

When a circuit is energised, a cyan front, wider than the conductor, sweeps outward from the source and then disappears. Only afterwards do the amber dots start moving.

That is not decoration. Energy is carried by the electromagnetic field, which travels in the space around the conductors at close to the speed of light, while the electrons themselves crawl along at millimetres per second. The two scales cannot share one animation, so UnifCAD separates them in time: field first, then charge.

For the same reason the conductor itself is never tinted to show the wave — that would teach exactly the wrong thing, that energy travels inside the wire.

The front fires on the edge: starting a simulation sweeps the whole circuit, closing a contact sweeps only its branch. At rest it adds nothing.