Y2 Project Week 5

Week 5

The improvement of the circuit

The problem in last week was the first thing to do in this week, which is the error of the phase difference may be higher than our expectation.  We discussed and found the reason was that the values of capacitor in the cascade circuit and the parallel circuit are different.  Therefore, we need to do the calculation and choose the suitable capacitor before connecting the circuit.

In this week, we decided to replace the BJT by the MOS.  The advantages of the MOS are that it save the space on the breadboard and it only determined by the voltage.  When it compared to the BJT, it does not need to change the value of the capacitor in the circuit.  The following figures will show the MOS and the whole circuit:

Figure 1

Figure 2

Figure 3

The new circuit will collect the voltage and current by the ARM, and then the voltage will be transferred into square wave.  Next, the ARM will calculate the original power factor of the circuit.  After the calculation of the original power factor, the ARM will change the voltage of the MOS in order to realize the switch function of the MOS.  Afterwards, the circuit will be connected to the different capacitors.  The ARM will calculate the power factor and reserve the best capacitor.  The result will be displayed on the LED screen of the ARM. 

However, the new circuit still has some problems.  The most important problem is that the amplifier can not work.  The amplifier is used to amplify the voltage to the MOS, and the voltage will determine the state of the MOS.  If the amplifier can not work, the whole circuit will not work.  In addition, when we tested the circuit, we found that the accuracy will decrease when we increase the frequency.  These two problems cause the new circuit can not work well.

Test of the circuit

After using the MOS to replace the BJT, we need to test the whole circuit to check the circuit can work or not.  The following figure will display the result of the circuit：

Figure 4

From the result, we can see the power factor has been improved.  It has realized the function of saving energy.  This technology can be applied in our daily life to help us to save energy and improve the efficiency when we using the electronic appliance.