Circuit Studio

Draw a schematic from a real part library, then solve it — operating point, frequency response, and a run over time — and put the live circuit on a slide.

Circuit Studio is a schematic editor with three solvers behind it. What you draw is a real netlist: connectivity is derived from the drawing, the measurements are computed from your circuit, and when the circuit cannot be solved honestly the studio refuses with a sentence that names the problem. The same circuit can then live on a slide, still solving, wired to the deck's parameters like everything else in Quodra.

Opening the studio#

In the dashboard sidebar, open Studio and choose Circuit Studio. That is your circuit library: every stored circuit as a card with its name, its revision, and the date it last changed.

New circuit opens the starter list. Each starter is a complete circuit, indistinguishable from one you drew yourself, and carries a one-line note about what to look for when it solves:

Deleting a circuit asks first, and says what happens to slides that use it: "Linked deck objects keep their cached copy and can detach."

You can also arrive from a deck. Double-click a circuit object on a slide and press Open Circuit Studio on the toolbar that appears, or use the same button in its inspector.

The workspace#

Five regions:

• The toolbar — the circuit's name, the save state, the tools, the analysis switch, export, and Add to deck.
• The Library on the left, with four tabs: Parts, Meters, Starters, Outline. Its header counts what you have placed. Search parts filters Parts and Meters by name.
• The canvas — the sheet, with a zoom readout that doubles as Fit circuit.
• The Inspector on the right, which shows the selected part, the selected wire, a multiple selection, or the document itself when nothing is selected.
• The Analysis panels along the bottom: Measurements, Simulation, Response, Transient, Problems, Solver. Clicking the open tab again collapses the strip.

Both side panels can be hidden (Hide library, Hide inspector) and both can be dragged wider by their edge; the widths are remembered. The studio has its own light and dark setting — Switch to paper and Switch to dark.

The part library#

Twenty-two parts in five groups, plus two probes on the Meters tab.

On the Meters tab, the ⓘ beside Probes says what they are: "Ideal instruments: a voltage probe draws nothing, a current probe drops nothing."

Symbols draw in IEC or ANSI, switchable per document from the Inspector when nothing is selected. Settings › Studios chooses what a new circuit starts with: its Symbols, the analysis it runs first (DC operating point, Transient or AC sweep — a starter built for one keeps it), and whether it labels Node voltages.

Drawing#

Click a part in the Library — or press 1–9 for the nine most common — then click the canvas to place it. The tool stays armed, so a row of resistors is a row of clicks, and a chip over the canvas says "Placing Resistor · click to drop · on a wire, in series · R rotates · Esc stops". R turns the armed part before you drop it; with nothing armed, R rotates the selection and M mirrors it. Drop a two-terminal part onto a straight run of wire, lying along it, and it goes in series: the wire is cut between its pins, and the canvas shows the cut before you click.

Switch to the Wire tool (W) and draw from anywhere — a pin, another wire's end, any point along another wire, or empty sheet — either by dragging, or by clicking to start and clicking for each corner. A wire never has to reach a component or close a loop: reaching a pin or a wire ends it there, and a double-click, Enter or Esc ends it where it is, a dangling end and all. ⌫ takes back the last corner. Runs come out orthogonal, turning their corner the way that avoids parts and other wires. As you approach something the wire's end snaps to it: what it will join glows, and a dot shows every point it will join before you let go. Hold Alt (Option) to stop the snapping for a moment — the end goes to the grid point under the pointer. The Select tool draws too, from a connection handle: hover a part, and a small disc appears just beyond each pin that has nothing on it; drag the disc to draw a wire from that pin.

Connection happens at vertices, which is the standard schematic convention: a pin, a wire end, or a wire bend that lands on another wire's segment joins it — a wire drawn into or out of the middle of another makes a T — and a dot is drawn wherever three or more arms meet. Two wires that merely cross, neither of them turning, do not connect, and are drawn with no dot. Nets are never authored — they are derived from the drawing every time it changes.

Selection behaves like a drawing tool: click to select, shift-click to add or remove, drag on empty sheet for a marquee, drag a part to move it — from its body or from any of its terminals; its wires follow, and any junction on them stays joined — drag a wire segment to slide it (wires ending on it come along), drag a wire that is attached to nothing to move it whole, and drag a wire's end to take it somewhere else. Before you press, what would move is outlined, and pressing at a terminal never starts a wire. While you drag a part, a pin that comes near another pin, a wire's end or a wire snaps onto it and connects when you let go, with a dot where it will join; with nothing that near, its pins line up with other parts' pins and a guide line shows the line they share. A lone two-terminal part dragged onto a wire goes in series, as a dropped one does. Alt holds the snapping off here too. Right-click gives Rotate, Mirror, Duplicate, Delete, Clean up circuit (or Clean up selection), and Fit view.

Values, references, and the inspector#

Select one part and the Inspector shows it: its Reference (R1), an optional Label shown instead of the reference, its value in the unit the part is measured in, and every knob that part declares. Where it needs saying, an ⓘ beside the part's name says what the part is, and one beside a knob what the knob does.

Value fields take engineering shorthand — type 4.7k and get 4.7 kΩ. A value that cannot be read is rejected in place, with "Not a value in Ω — try “4.7k”." In any value field, ↑ and ↓ step the number by ×2 and ×0.5, with Shift for ×10 and ×0.1. Enter commits; Escape abandons your edit and takes whatever the document holds, which matters when someone else is editing the same circuit.

A DC source also carries an AC amplitude and, once that is set, an AC phase. That is the small-signal stimulus, kept deliberately separate from the source's DC value: the bias and the signal are different questions.

The Pins section lists the part's pins — each one connected, open, or open on purpose — with a switch for its no-connect mark, the X a schematic puts on a pin that is left open by design. A marked pin is no longer pointed out as unconnected, here, in Problems or by an authoring check; right-clicking a pin on the canvas offers the same mark.

Select a wire instead and you get Name. Naming a wire names its whole derived net — its ⓘ says "Names the wire's whole net; the measurement table follows it." Named nets are also the only ones a slide's waveform view will offer, because an automatic name like N3 is a coordinate with a number on it.

Select several things and the Inspector offers Align (Left, Centre, Right, Top, Middle, Bottom), Arrange (Rotate, Mirror), Tidy (Clean up), and Delete selection.

Dress and annotations#

With nothing selected, the Inspector describes the document: an About note, the symbol standard, and Dress — Engineering or Presentation. Under Annotations are five switches: Values, References, Current flow, Node voltages, Animate current. When current is both shown and animated, a Current flow section appears with the marker's Marker shape (Dashes, Dots, Pulse), Weight, Speed, and Colour.

Solving as you draw#

The studio solves continuously. The chip beside the analysis tabs shows rev N when a result is current and solving… while it catches up; the solve itself runs on idle, so it never sits between a keystroke and the ink.

Prefer a Run button? Toggle Solving continuously off — it becomes Solve on demand and a Run button appears. A result from an older revision is never quietly shown as current: the panel says "Showing revision 7; the circuit is at 9. Run again — old numbers are never shown as current."

What each panel does is covered in Analyses.

Saving, and who may edit#

A stored circuit saves itself. The chip beside its name reads Saved, Saving…, Unsaved, Not saved — retrying, or Someone else saved first — that last one is a revision-checked save that found the document had moved, not a lost edit. A circuit opened inside a deck reads in deck instead, because its changes travel in the deck's own history.

Share works like a deck: add people by email as Can edit or Can view. Editors work in the circuit live, with presence and cursors on the schematic. A viewer opens it read-only — they can zoom, probe, and read the analysis, but the name field and the schematic refuse edits, and a chip in the toolbar says "shared with you · viewing" so nobody is surprised. Only the owner changes who has access; everyone the circuit is shared with sees Share too, which lists who has it: the owner, then them, then everyone else, each with their email address and role (who sees whom).

Comments opens a review drawer in the right rail, with threads pinned to components. A pin follows its part as it moves, and a thread whose component has been deleted is marked orphaned rather than thrown away — deleting the part does not settle the argument about it. See Collaboration.

Getting the drawing out#

Download SVG writes a standalone vector file with its own stylesheet, and Download PNG rasterises the same markup at 2×. Both come from the same view the app draws, so an export cannot drift from the screen; interactivity degrades to the currently solved state.

Keyboard#

Shortcuts are ignored while you are typing in a field, so 1 in a value box is a one.

Next#

• Analyses — what each solver computes, and every refusal it can give.
• Circuits in your deck — Add to deck, the four views, and parameter slots.
• Tutorial: an RC filter from scratch — build one, solve it, present it.