Quick start

1. Drag parts from the left palette onto the canvas (or click a part, then click the canvas). Parts snap to a 20px grid.
2. Wire pins: click a pin dot, then click the target pin. Wires route orthogonally. Click a wire to start a junction.
3. Move parts by dragging. Press R (or the Rotate button) to rotate, Del to delete, Ctrl+Z / Ctrl+Y for undo/redo.
4. Pan with Space + drag, middle-mouse drag, or two fingers. Zoom with the mouse wheel or pinch (0.4x – 3x).
5. Press Run to simulate. Click a switch while running to open/close it. LEDs burn out above 30mA!
6. Save circuits in the browser, export/import JSON files, or use Share link to store the circuit in the URL.
7. Boards: UNO, Nano and Mega provide 5V/3V3/GND pins and GPIO-HIGH pins, the ESP32 provides 3V3/GND — wire them like a battery.
8. Logic gates: wire Logic inputs (click to toggle 0/1) into gate inputs, and the gate OUT pin drives LEDs like a 5V source. Pin dots show live H/L levels.
9. Truth Tables: the toolbar button opens a workbench drawer with all 7 gate tables; while running, the row matching each placed gate's live inputs is highlighted.
10. Modules: sensors, displays and comm modules need VCC + GND wired to a board or battery. Trigger sensors (PIR, Hall, touch…) can be clicked to toggle their OUT pin.
11. Relay & transistor: energize the relay coil (or drive the NPN base through a resistor) and the contact side actually switches the circuit.
12. Palette: sections are grouped by use case — use the search box to filter parts by name. ICs include the 741, 74HC595, L293D, ATmega328P and a generic catalog chip.

Logic Lab (digital logic mode)

1. Switch modes with the "Circuit Lab | Logic Lab" pill in the toolbar. Each lab keeps its own canvas, undo history, save slots and examples — switching never loses your work.
2. Logic Lab simulates continuously — no Run button. Use Pause to freeze the simulation and the clock-speed select (1 Hz / 2 Hz / 5 Hz / Fast) to change the clock rate.
3. Wires are colored by logic state: glowing teal = HIGH, slate gray = LOW, dim dashed = UNDEFINED (unconnected or tri-stated). Pin dots show the same colors.
4. Inputs: click a toggle switch to flip 0/1, hold the push button for a momentary pulse, and edit a clock's frequency in its properties. Constants, pull-ups and pull-downs drive weak or strong levels.
5. Flip-flops: SR works as a NOR latch (S=R=1 is flagged invalid); D, JK and T latch on the rising clock edge and their async PRE / CLR inputs override everything. The body chip shows the current Q.
6. Gates can be switched to 3 or 4 inputs in the properties panel. The tri-state buffer drives its output only while EN is HIGH — combine several on one bus with pull resistors.
7. Try the built-in logic examples: Half Adder, Full Adder, SR Latch, D/T/JK flip-flop circuits and a tri-state bus demo. Truth Tables work here too, and Share links carry &mode=logic.