PURPOSE: To show the resistance of a wire is proportional to length, and to show how the power to a lamp is decreased when the resistance of the wire is increased.
DESCRIPTION: A long board with two wires is clamped to a table and powered with a power supply. A slider with a lamp completes the circuit between the two wires. as the slider is moved the length of the circuit wire is increased and the light becomes dimmed.
EQUIPMENT: The slide wire is stored on the shelf of long stock. The low voltage, high current power supply is stored in the general use cabinets.
SETUP NOTES: Clean the wires with contact cleaner before use.
Updated by Jun Qi in 3/13/2000