Current Balance
Current Balance
PHY 114
10/29/2013
Abstract: The purpose of this experiment was to understand the current balance, current balance is an apparatus that allows measurement of the small force between two current carrying conductors. It consists of two parallel horizontal bars, which are connected in series. The current flows in opposite directions in the two conductors so there is a repulsive force between them, by Newton’s third law there are equal and opposite forces on both wires. In the lab these forces are on the order of e-4 N and are fairly small. In real devices such as electric motors many steps are taken to make the force larger using many turns instead of a single wire, using the ferromagnetic properties of iron to increase the magnetic field.
In the current balance unit the lower bar is fixed. The upper bar is balanced a few millimeters above the fixed one by adjusting the counterpoise. There is yet another adjusting weight that brings the location of the center of mass of the whole apparatus slightly below the location of the fulcrum. The upper bar supports a small pan into which analytical weights are placed causing the upper bar to drop down toward the lower one. When the current is turned on and increased sufficiently, repulsion between the two bars causes the upper bar to rise to its initial equilibrium position.
Objective: The objective of this lab was to observe and measure small forces between two parallel current carrying conductors, and also to verify the definition for the ampere.
Procedure: The DVM reads voltage across the 1 resistor so it automatically displays the value of the current in the circuit in amperes. Remember do not leave currents on for a prolonged time it may cause excessive heating and some instability. There are three steps: Step 1: We have to find the distance d corresponding to the equilibrium position of the balance. Observe on the scale the value of x1corresponding to the conducting wires in contact
PHY 114
10/29/2013
Abstract: The purpose of this experiment was to understand the current balance, current balance is an apparatus that allows measurement of the small force between two current carrying conductors. It consists of two parallel horizontal bars, which are connected in series. The current flows in opposite directions in the two conductors so there is a repulsive force between them, by Newton’s third law there are equal and opposite forces on both wires. In the lab these forces are on the order of e-4 N and are fairly small. In real devices such as electric motors many steps are taken to make the force larger using many turns instead of a single wire, using the ferromagnetic properties of iron to increase the magnetic field.
In the current balance unit the lower bar is fixed. The upper bar is balanced a few millimeters above the fixed one by adjusting the counterpoise. There is yet another adjusting weight that brings the location of the center of mass of the whole apparatus slightly below the location of the fulcrum. The upper bar supports a small pan into which analytical weights are placed causing the upper bar to drop down toward the lower one. When the current is turned on and increased sufficiently, repulsion between the two bars causes the upper bar to rise to its initial equilibrium position.
Objective: The objective of this lab was to observe and measure small forces between two parallel current carrying conductors, and also to verify the definition for the ampere.
Procedure: The DVM reads voltage across the 1 resistor so it automatically displays the value of the current in the circuit in amperes. Remember do not leave currents on for a prolonged time it may cause excessive heating and some instability. There are three steps: Step 1: We have to find the distance d corresponding to the equilibrium position of the balance. Observe on the scale the value of x1corresponding to the conducting wires in contact