Review connections and estimate a PCB trace

A schematic can look finished and still have a pin that only touches empty space. Ohmforge's Connectivity review finds those gaps before you simulate, and the PCB Trace Estimator gives a first copper width when you move from the schematic to a board.

Run the connectivity review

Open the Voltage divider template and choose Connectivity review — the check-mark button after Power switch in the toolbar, or Simulate → Connectivity review…. The dialog shows four numbers:

• Nets — how many separate electrical nodes the schematic has.
• Unconnected pins — component pins with no wire, other pin or ground on their net.
• Dangling wire ends — wire ends that touch neither a pin nor another wire.
• Ground reference — Present or Not found. Every simulation needs a ground (node 0).

On the template everything is connected, so the list says No findings in these checks.

Break something and find it again

Close the dialog. Click the ground symbol and press Delete, then click the wire that runs below the divider from V1 to R2 and press Delete as well. Run the review again. Now it lists:

• Pin - on V1 is not connected. — the negative terminal of the source, with its net name and grid position,
• Pin 2 on R2 is not connected.
• No ground symbol or ground net label was found.

Choose Show next to a finding: the dialog closes, the part is selected and the view centres on it. Press Ctrl+Z twice to bring the wire and the ground back; the next review is clean again. A wire end that touches nothing is listed as, for example, Wire w3 has an unconnected end. with its position.

The review also reports duplicate references (R1 and r1 count as the same reference) and merged net labels, for example when labels OUT and VIN end up on the same net. Two wires that merely cross do not connect; a wire end on another wire forms a T-junction, and matching net labels connect distant parts.

The review is a connectivity aid, not a full electrical rules check: it does not know pin roles, ratings or whether an open end is deliberate. Use it together with simulation and your own review. Scripts and AI agents can run the same check on a project file with the ohmforge-connectivity-review tool.

Estimate a trace width

Open the PCB Trace Estimator from the tool list on the Ohmforge home page. Keep Width for a current, an External layer, 1 A, 1 oz/ft² copper, a 10 °C temperature rise and a 100 mm length. The estimate is 0.302 mm (11.9 mil); over 100 mm that trace has about 0.164 Ω at 20 °C, so 1 A drops 0.164 V and dissipates 0.164 W. Switch to Current for a width to check an existing trace instead.

The calculator uses the empirical IPC-2221 relation for an isolated trace. Inside the chart range (up to 35 A, 400 mil, a 10–100 °C rise and 0.5–3 oz copper) it is a reasonable first estimate; outside it the result warns that the value is an extrapolation. Nearby copper, vias, plating and cooling change real temperatures, so confirm finished copper thickness and design rules with your fabricator.