Simulations

Fire a charged particle into a uniform magnetic field (a closed cyclotron circle), add a uniform electric field (a bending parabola), or combine both to see the guiding center drift sideways — adjust charge sign, mass, speed, and both fields.

Fire a charge into a uniform magnetic field, perpendicular to its velocity — adjust the entry speed, field strength, and charge-to-mass ratio to see the radius and period of the resulting circular orbit.

Slide a bar magnet through a coil — adjust its speed, the coil's turns, and the magnet's strength to see the induced EMF rise, peak, flip sign as the magnet passes through, and fade as it recedes.

Drive a series RLC circuit with an AC source — sweep the drive frequency through the resonant frequency and watch the steady-state current amplitude peak, with the peak's sharpness controlled by the circuit's resistance.

Watch a current-carrying conductor feel a push in a magnetic field. In one view a thick wire hangs between a north and a south pole; switch on the current and it swings out, with arrows for the field, the current and the force and the force worked out as F = B × I × L (for instance 0.4 T × 3 A × 0.1 m = 0.12 N). In the other view a coil sits on an axle between the poles with a split-ring commutator that reverses the current every half turn, so the coil spins up to a steady speed in rpm while the voltage it pushes back with cuts the current. Change the field strength, the voltage, the length of wire, the number of turns, and reverse the current or the field to see the force and the turning direction flip.

Charge or discharge a capacitor through a resistor — adjust the source voltage, resistance, and capacitance to see the exponential voltage/current curves and the circuit's time constant.

See how a transformer steps a voltage up or down. Alternating current in the primary coil makes a changing magnetic field in the iron core, and that field induces a voltage in the secondary coil. The voltages follow the turns, so the secondary voltage is the primary voltage times the secondary turns divided by the primary turns, while the current changes the other way and the power stays almost the same. Watch the field in the core swing back and forth and the two voltages on one graph. A second view sends a fixed amount of power down a cable and compares the heat lost with and without stepping the voltage up, which is why power lines use high voltage. Set the voltage, the turns on each coil, the load, the efficiency and the mains frequency. For instance, 12 V across 100 turns into 500 turns gives 60 V.