The Virtual Lab is an interactive fault-diagnosis simulator built on real SVG circuit schematics. You place probes, take readings on a simulated multimeter, and work through the same diagnostic logic you'd use on an actual panel — with zero risk and instant feedback.
Available Circuits
| Circuit | What It Simulates |
|---|---|
| Circuit A — 480V/208V/110V Multi-Stage Power & Control | 480VAC 3Ø supply with wall disconnect and fuses, 3KVA $\Delta\text{–}Y$ transformer stepping down to 208VAC, M1 starter & 3Ø motor, 110VAC CPT T1 feeding a 24V motor, 110V fan, 15V lamp, and 24VDC bridge rectifier power supply. |
| Circuit C — 208VAC 3Ø Motor (24V CPT) | Industrial motor branch with disconnect fuses, magnetic contactor M, 24VAC control power transformer, and emergency stop/start pushbutton station. |
| Circuit E — Diode Testing (12VDC) | Low-voltage diode circuit for practicing forward/reverse-bias testing and identifying shorted or open diodes. |
Guided Mode vs. Challenge Mode
Guided Mode walks you through normal operation first, then lets an instructor-style control panel inject a specific fault (a blown fuse, an open motor starter, a tripped overload) so you can trace it methodically. Challenge Mode drops you into a circuit with an unannounced fault and scores you on probes used and diagnosis accuracy — the closer to real troubleshooting conditions.
How to Diagnose a Fault
- Establish a COM reference. Secure the black probe to a verified ground or neutral return.
- Trace voltage sequentially. Use the red probe upstream and downstream of fuses and contacts. Full voltage before an element but zero after it under demand means that element is open.
- Identify blown fuses. Full line voltage measured directly across a fuse terminal block means the fuse has blown.
- Check the overload relay. An open OL auxiliary contact breaks the coil circuit and drops the motor starter out.
The full walkthrough of this logic — including how parallel resistive paths can mask a fault — is in the Study Guide's Fault Diagnosis section.
Reading History & Scoring
Every probe placement and reading is logged to a reading history you can review after each attempt. Challenges Solved is tracked in My Progress alongside your Safety and Theory scores, and the Troubleshooter badge unlocks once you've resolved every unique fault across all three circuits.
No risk, real reps. Every fault you'll see here is one you'd rather practice on a screen first.