Production of AC
AC is short for alternating current. This means that the direction of current flowing in a circuit is constantly being reversed back and forth. We aim to produce AC by, connecting the copper coil by a clamp onto the retort stand, having a magnet attached to the end of the spring hanging off another retort stand, enabling the magnet to move in and out of the coil, thus producing an AC.
We predict that the data received and transmitted to the computer, will show as sine wave which is the current. (Like ac in the picture above).The voltage produced in the coil will be proportional to the number of turns in the coil’. The voltage would be halved as the 300 turn copper coil used was half of the 600 turn copper coil.
As we produce AC we will connect a data logger to record the values capturing the evidence of the model of producing AC.
The independent variable in our experiment is the turns of copper coil. In our experiment we have a 600 turns copper coil and a 300 turns copper coil.
The dependent variable in our experiment is the coil voltage, as measured by the data logger which will record the data from the copper coil and into the computer.
How to measure the variable
The voltage in our experiment is measured by a data logger which will record the data from the copper coil and into the computer.
The equipment used in the model include: Spring, Clamps, Retort Stands, 600 and 300 turn copper coil, tape, magnet, sheet of cellophane paper rolled into the hole of the copper coil to let the magnet flow freely into the copper coil and out. Computer program ‘Data Harvest Graph’ program
Why are the up voltages less than the down voltages? It is because there seems to be a residual negative voltage even when the magnet is at rest (of about -0.05 volts). If you add 0.05 to the up voltages and subtract 0.05 from the down voltages, they end up pretty close. Why do the voltages decrease with time? This is because the magnet is slowing down due to friction. Why do we get spikes instead of a sine wave? ‘My hypothesis is only partially correct. We did get an alternating voltage, but NOT a sine wave’. This is because of the concentration of the field lines near the poles of the magnet. Sine wave are/usually produced by rotating magnets rather than oscillating magnets.
The first graph shows the similarities in voltage of when the magnet has passed in and out of the 600 and 300 turn copper coil. As shown in the Second graph which is the recorded data from the data logger, the first tip of the first wave (maximum) (as shown) is the magnet entering the magnetic field of the coil. Then as the magnet travels into the middle- we see that the graph shows the first diagonal line as it passes zero, thus when the magnet is passes through the center of the copper coil, the voltage is zero. Then as the magnet leaves the center of the copper coil, negative voltage is made and where the second tip of the first wave (minimum) is shows the magnet leaving the magnetic field of the copper coil.
As the magnet is out of range of the copper coil and reaches its maximum falling distance, the voltage drops down and goes back to zero as shown. Now, this time, as magnet makes its way back up through the center of the copper coil, another sine wave is produced exactly in the same shape of the first wave- a POSTIVE voltage as it goes up through the center of the copper coil – the direction of the current is reversed. Thus this is alternating current, as the magnet moves into the coil and out and vice versa, of the direction of the movement of the magnet is; its voltage recorded is constantly being reversed back and forth. It clearly shows that the voltage is alternating directions in a repetitive pattern.
We then tested