Faraday's Induction Experiment - Physics Demonstrations - Faraday's Induction Experiment | Physics Undergraduate Labs

Purpose

Demonstrates Faraday's Law using a demountable transformer core with hand-wound coils. Closing a switch on the primary circuit causes one LED to flash in the secondary; opening it flashes the other LED. Shows that only changing flux induces an EMF, and that the polarity reverses (Lenz's Law).

Complete setup: Xantrex DC power supply set to 3V, knife switch on stand, demountable transformer core with red and black banana cables wound around opposite legs on a wooden base, and a white breadboard with red and green LEDs

Close-up of breadboard with red LED illuminated and green LED dark, showing banana plug connections

Close-up of breadboard with green LED illuminated and red LED dark

Figure 1: Complete apparatus: power supply (3V DC), knife switch, demountable transformer core with banana-cable coils (~20 turns each side), and LED breadboard for the secondary circuit.

Figure 2: Red LED flashes when the switch closes (increasing flux through the core).

Figure 3: Green LED flashes when the switch opens (decreasing flux), showing the induced EMF reverses polarity.

Breadboard With LEDs

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