Hall effect: Magnetic field induces a voltage in a neon plasma.

• D+30+28

Hall effect: Magnetic field induces a voltage in a neon plasma. A long glass tube has been evacuated and a trace of neon has been added. When a large voltage (about 1000 V.D.C.) is placed across the ends of the tube, the tube glows. When a powerful permanent magnet is brought in towards the center of the tube (in a direction perpendicular to the tube and parallel to the plane of the table) a voltage is created between points A and B (perpendicular to both the electron flow in the tube and the magnetic field of the bar magnet).This is the Hall Voltage, which reaches about 1.5 Volts in this demo. It is displayed using a projection voltmeter (10 M ohms impedance).The knob on the small black box allows the meter to be zero-centered.