STEP 1 OF 9: THE BOARD
Navigate the Board
The large center area is the circuit board. Hold Space and drag to pan, or use middle-mouse drag. Scroll the mouse wheel to zoom in and out. Press FIT in the toolbar to bring everything back into view at any time.
Go to ⋯ menu → Examples to load a ready-made circuit and explore it immediately.
STEP 2 OF 9: PLACE PARTS
Build a Circuit
Click any component in the left palette, then click the board to place it. A complete circuit needs: battery (source) → fuse (protection) → switch or relay (control) → load (bulb, motor, solenoid) → ground (return path). Drag a component to reposition it. Press R to rotate a selected component.
Drag on empty board space to box-select a group. Shift+click to add individual components to a selection.
STEP 3 OF 9: WIRE
Connect Components
Press W (Wire mode), click near a component pin to start, add waypoints as needed, then double-click to finish. Pins appear as small circles on component edges. Select a wire to change its colour: Red for battery feed, Black for ground, Yellow for switched power. Press F2 to add a label to any wire.
Press Esc to cancel a wire in progress. Ctrl+Z (Cmd+Z on Mac) undoes the last action.
STEP 4 OF 9: SIMULATE
Run the Circuit
Press RUN. Current flow animates on live wires. Press V to display voltage at every node. Press D to show voltage drop across components: a healthy connection or switch drops ~0V, a corroded terminal or fault drops several volts. Press FIT to reset the view.
Voltage present and voltage drop are two different tests. Both are required to correctly diagnose a high-resistance fault.
STEP 5 OF 9: METER
Take Readings
Open the Toolbox panel on the right side. Select the DMM and set the function dial: V DC for voltage, Ω for resistance, A for current. Click a wire or component pin on the board with the Black lead, then the Red lead. The live reading appears on the meter display.
Resistance must be measured with the circuit de-energised (RUN off). Measuring ohms on a powered circuit gives false readings and can damage a real meter.
STEP 6 OF 9: DIAGNOSE
Fault-Finding Scenarios
Click Training in the toolbar to open the scenario library. Pick any scenario: you receive a real-world customer complaint and a circuit with a hidden fault. Use the meter to trace the circuit systematically and isolate the fault, then submit your diagnosis.
Work from the power source toward the load and back to ground. Use voltage-drop testing to catch high-resistance faults that a continuity check alone will miss.
STEP 7 OF 9: FAULTS & INSTRUCTOR
Create Training Assignments
The Faults section in the left palette lets you insert training faults: Open, Short, High Resistance, Corrosion, Loose Connection, and more. Place a fault on a circuit, then click Instructor in the toolbar. Write a complaint description, hide the fault, and lock the circuit so the student must find it using the meter.
The student receives the complaint but cannot see the hidden fault: exactly like diagnosing a real machine in the shop.
STEP 8 OF 9: SHORTCUTS
Key Shortcuts
S = Select · W = Wire · P = Probe · Space + drag = Pan · R = Rotate · F = Fit view · V = Voltage labels · D = Drop labels · Del = Delete · Ctrl+Z / Cmd+Z = Undo · Ctrl+Y / Cmd+Y = Redo · Ctrl+A / Cmd+A = Select all · F2 = Label wire · Esc = Cancel action
Double-click a switch or relay to toggle it. Double-click a battery or resistor to edit its value.
STEP 9 OF 9: WHAT THIS LAB MODELS
Scope of the Simulator
This lab models DC electrical circuits and diagnostics — 12V/24V automotive, equipment, trailer, charging, starting, sensor, and module circuits. Voltage, current, resistance, voltage drop, relays, and realistic faults are all physically solved. It is built to teach systematic DC fault-finding.
Not modelled: AC line voltage, three-phase, transformer coupling, power factor, and PWM duty-cycle behaviour (a PWM output reads as its DC average). For HVAC and electrician AC theory, use the dedicated systems as they become available.