L & N Galvanometer

Always use high resistance (minimum 10,000 Ω) in series with the galvanometer to protect the delicate coil from excessive current. Even modest currents can damage or destroy the suspension. Start with maximum resistance and decrease gradually if needed.

When using a laser for the reflected beam, ensure it is Class 2 or lower and never direct it toward anyone's eyes. Position the reflection path away from audience eye level.

Purpose

Students learn how a galvanometer detects small currents through the deflection of a suspended coil in a magnetic field. A mirror on the suspension reflects a laser beam onto a distant surface, providing optical amplification that makes microampere-level deflections visible to the entire lecture hall.

Leeds & Northrup galvanometer in black case mounted on cast iron tripod stand with leveling screws, mirror and suspended coil visible through front window, terminal block on top

Figure 1: The L&N galvanometer with specification label visible (sensitivity, period, resistance). The mirror on the suspended coil is visible through the front window.

Warning: Current Limiting Essential

Warning: Laser Safety

Purpose

Safety Warnings

Warning: Current Limiting Essential

Warning: Laser Safety

Purpose