Essential demonstration equipment for middle school and university physics and engineering courses, which can visually demonstrate the entire process of "electromagnetic induction → DC power generation", helping students understand the relationship between Lorentz force, magnetic flux changes, and induced electromotive force. Demonstration effect: When hand cranking the disc, the voltmeter immediately displays a DC voltage of 20-300 mV (proportional to the speed); Reverse the handle, and the voltage polarity will reverse accordingly, verifying Lenz's law; Connect a small bulb with a voltage of 3 V/0.3 A, and the brightness can be visually observed to vary with the rotation speed; Scalable access to sliding resistors to explore the impact of load changes on output characteristics.