Diodes &
Circuit Protection
One-way current flow, polarity protection, rectification, transient suppression, and real diagnostic reasoning—learn it, visualize it, then prove it.
10 guided lessons
Open each lesson and mark it complete. The mini-course introduces diodes here; the dedicated Semiconductors & Electronic Switching subcourse can later explore junction physics in greater depth.
Interactive diode circuit workbench
Change the supply, resistor, diode type, and orientation in a simplified steady-state series circuit. A resistor is always present; never place an LED directly across a battery. Reverse breakdown and thermal effects are excluded from this introductory model.
AC rectification lab
See the difference between an AC source and a rectified output. Select a single-diode half-wave circuit or a four-diode bridge. The graph uses an idealized, unloaded resistive-load model with fixed illustrative forward drops; ripple filtering and alternator regulation are not included.
Blue = AC input; gold = rectified output. Horizontal axis shows two source cycles (duration varies with frequency).
Flyback diode demonstration
A relay coil stores magnetic energy while current flows. Opening its control switch can produce a large induced voltage. Place a suppression diode reverse-biased across the coil during normal operation to provide a path for the decaying current when the switch opens.
Virtual diode-test meter
Pick a fault, connect meter leads, and interpret the simulated reading. In a real test, de-energize the circuit, discharge stored energy, and isolate the diode as required by service information to avoid parallel circuit paths and damage. The leaky-diode readings here are illustrative, not a universal diagnostic rule.
An OL display alone does not establish a failed diode: a good silicon diode commonly reads OL when reverse-biased. Test both directions and consult the manufacturer specification.
The Challenger's diagnostic cases
Choose the next justified diagnostic step. Each case checks reasoning, not just component recognition.
0 of 3 cases solved
Show what you know
Answer all eight questions. You need at least seven correct answers to complete the assessment; review explanations and try again whenever you want.
One-way flow. Better diagnosis.
Complete the ten lessons, four virtual labs, three diagnostic cases, and assessment to unlock your mini-course badge.
Your progress will appear here.