Electrical · circuit boards, schematics, control panels

A circuit you can click.

Start with a small board: a battery, a switch, a microcontroller on headers, a resistor and an LED. Click any part to change it, drag it to move it, flip the switch to see it run, and the report and bill of materials are already written. Nothing to learn first.

Switch offOpen in editorOpen in the board editor

Click a part to edit its values (it opens in the Board view); click the switch to turn the LED on. Drag any part to move it, drag empty space to orbit, scroll or pinch to zoom.

LED current

0 mA

dark

U1 output

0 mA

30 Ω pin, 20 mA max

Supply

3 V

CR2032 coin cell

Across the LED

0 V

Green forward voltage

Across R1

0 V

100 Ω

✓LED current. 6.15 mA through D1 at 2.2 V: a comfortable brightness.
✓Output pin. 6.15 mA from U1's output pin, under the 20 mA a pin should source.
✓Microcontroller supply. 3 V is within U1's 1.8–5.5 V supply range; the module draws about 1.5 mA.
✓Resistor power. R1 dissipates 3.8 mW, 4% of its 100 mW rating.
✓Trace width. 0.3 mm traces carry about 1.00 A with a 10 °C rise; the circuit draws 7.65 mA.
✓Placement. Parts clear of each other and of the board edge; 6 traces, no vias.
✓Fabrication rules. 0.3 mm traces and 0.2 mm clearance meet a 0.15 mm / 0.15 mm two-layer process.
✓Battery life. About 29 hours on a fresh CR2032 coin cell with the switch left on: 6.15 mA through the LED (steady) plus 1.5 mA for the module.

Everything here is live: edits change the simulation, the report and the bill of materials at once. Checks are early-sizing aids, not certifications.Open in the board editor

Flip the switch

Click SW1 on the board. Current flows along the traces, the LED lights and the live numbers show how much.

Click a part to change it, drag it to move it

Pick a different battery, a brighter LED colour, another resistor value or a program for the microcontroller: the values open only when you click the part. Drag a part across the board and the traces re-route; turn it, flip it under, delete a route and route it again, or undo. The circuit, the checks and the parts list update as you go.

Read the report

Toggle Report for the written project report with the arithmetic and the checks, or Bill of materials for the parts, ready to copy or download.

Take it further

Open a starter LED board in the full board editor, which edits the same way: place parts from a library of thousands, route traces, run the circuit in SPICE and download fabrication files.

Circuit chip in abcad · free, in the browser, SPICE-compatible

From a sentence to a simulated, optimized circuit.

Type what the circuit should do, and abcad draws it, works out the values, sets the design targets, simulates it and optimizes it. Or draw it part by part, or open a SPICE netlist. The whole design loop is one drawing, with no licence to buy and nothing to install.

1 · Requirements

Set design targets: 10–15 mA through the LED, 3.3 V ±3 % out, a cut-off at 1 kHz. They are checked after every edit.
2 · Schematic

Click parts onto the sheet and wire them, describe the circuit in a sentence, or open a SPICE netlist you already have.
3 · Simulate

Operating point, DC sweep, transient and AC, live in the browser: every voltage and current on the drawing, waveforms and Bode plots beside it.
4 · Optimize

Optimize picks the part values that meet every target, snapped to standard values you can buy. Sweep and Tolerance do the rest of the value hunting.
5 · Prototype

A bill of materials with footprints, a KiCad netlist for the board, and a SPICE netlist for ngspice or LTspice.
6 · Measure and refine

Drop the bench measurements in as a CSV: they are drawn over the simulation with the error, and Fit sets a part value to match.

Describe a circuit Learn by building: light an LED Open the Circuit chip

Board editor

Printed circuit boards

Drag parts from a library of thousands of footprints onto a board, route the traces, and turn it over in 3D. Set values and pin names on each part, run the circuit in a real SPICE simulator, check it against fabrication rules, and download the files a board house needs.

· Routing with live clearance checks, both copper sides, vias
· DC, time and frequency simulation with plots
· Bill of materials, enclosure built around the board, Gerber files

Open a starter LED board in the editor Start a blank board See the board in the whole system

Elec chip in abcad

Schematics and control panels

Draw ladder diagrams, place switches, relays, lights and terminals, and wire them up. Tags, wire numbers and cross-references keep themselves right. Lay out the enclosure and terminal strips from the same project, and the bills of materials, wire lists and terminal plans are live reports.

· IEC and NFPA symbol sets, wire colours and tag styles
· Panel layouts with footprints, rails, ducts and nameplates
· PLC I/O, cables, signals across pages, an audit that never blocks

Open abcad

The checks and simulations are early-sizing aids for design. They are not certifications or stamped calculations.