Purpose:

To verify Ampere's Law.

Required Accessories:

• A 5V DC power supply
• A 2 ohm resistor
• Compasses

Discussion:

When a current is flowing through a conductor such as a length of wire, a magnetic field is circulated about that conductor. The direction of the magnetic field relative to the direction of current flows can be determined by "Ampere's Rule".

Experiment Description:

From Figure 1, connected a DC 5 volts direct current power supply through a 2 ohm resistor and through the aluminum conductor of the Ampere's rule demonstration. Therefore, the current will be 2.5 A. Aligned the unit so that the horizontal wire is pointing roughly north and south. Then, arranged about 8 compasses in a circle around the vertical rod.

Turned on the power supply and it will be seen that there was a major change in the direction of the compasses' needles. If the current is connected in the direction pointing out of the page, a magnetic field of anti-clockwise direction is circulated about the vertical rod. Likewise, a magnetic field of clockwise direction is circulated about the vertical rod if the current's direction is pointed into the page. This effect agrees with Ampere's Right-hand Rule.

Results:

A DC Power Supply, A 2 ohm Resistor, and the Ampere Rule's Apparatus

Any comments?

Instructor: Dr. Gedney
Department: University of Kentucky, EE Department
Created by: Tang, wee-hua