Building Circuits #

The tool palette #

The floating bar at the bottom holds every tool. On narrow screens five show directly — Oscilloscope, Wire, Resistor, Capacitor, Voltage Source — and the rest live in a More tools slot that always surfaces the armed tool’s icon.

Each tool has a single-letter shortcut (no modifier), also listed in the Tools menu on Mac:

Tapping the armed tool again returns to Select.

Placing parts #

There are two placement gestures, matching the part’s shape:

• One tap places body parts: chips, voltage sources, transistors, and transmission lines drop where you tap. Chips straddle the center divide automatically.
• Two taps place leaded parts: wires, resistors, capacitors, diodes, and inductors connect two tie points. The first tap anchors one lead (a ghost preview follows your finger or pointer); the second tap commits. You can also press, drag, and release in one motion. Tapping the anchor again un-picks it.

The Chip, Transistor, and Diode tools ask you to choose a part from the library first — the picker opens on your first placement tap if none is staged (see Part Libraries).

When a placement is refused #

Breadpad validates every placement and tells you exactly why one failed, right at the cursor:

• “That tie point is already taken — pick a free hole.”
• “This part would overlap another part on the center rows. Try an open stretch of the board.”
• “A lead is already connected on the center rows there. Move it, or pick another column.”

Your anchor and selection are kept so you can immediately try another hole.

Moving parts #

Select a part, then drag a grab handle. Leaded parts have separate grips for each lead; body parts move as a whole. While dragging, the target glows green (valid) or red (invalid); releasing over an invalid spot springs the part back. Every editor also has a Move button in its toolbar — tap it, then tap the destination.

Editing parts #

On iPad and Mac the editor is a persistent inspector panel; on iPhone and Vision Pro it’s a sheet, opened by a second tap on the selected part.

• Values accept SI prefixes: 10k, 100n, 2.2M, 4.7u.
• The number of digits you type is remembered as the value’s significant figures, which drives display precision and implied tolerance.
• Every numeric field has an engineering calculator (the calculator button beside the field) with x², √x, 10ˣ, 1/x, π, and e.
• Each editor shows a live analysis chart for its part — power dissipation for resistors, frequency response for capacitors and inductors, I–V curve for diodes, transfer characteristic for transistors, waveform preview for sources.

Tolerance and temperature-coefficient fields, and some advanced device parameters, require Premium.

Deleting and undo #

• ⌘⌫ deletes the selected part (also in the Edit menu, and as the red Delete button in each editor).
• Deleting, placing, and moving parts are all undoable with the standard ⌘Z / ⇧⌘Z, so deletes don’t ask for confirmation.
• The one exception: deleting a custom chip from your library is permanent and confirms first.