Laboratory 4 – Motor Control using Semiconductor

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Jun 12, 2024

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Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 1 Laboratory 4 – Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier Name  Farhan Ishraq Student Number  31234917 Lab Group  L2B Date of Experiment  2nd April, 2024 Lab Partner  Adarsh Govindan

Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 2 Pre-Lab There was no prelab assignment due for this lab. The image above shows that I did the required reading before the lab as mentioned in the lab assignment.

Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 3 The datasheets that were used for the lab: Hall-effect sensor: https://fwbell.com/wp-content/uploads/2017/04/Hall- Generators-catalog-NEWER.pdf 2N3904 https://www.onsemi.com/pdf/datasheet/2n3903-d.pdf TIP122 https://www.onsemi.com/pdf/datasheet/tip120-d.pdf 1N4148 https://www.onsemi.com/download/data-sheet/pdf/1n914-d.pdf Circuit Breadboard Image The overall circuit design was given to us, premade in a breadboard. The images below show the circuit schematic and the setup. The pinout for the motor and hall- effect sensor is indicated in the lab manual. Task 1: Motor Switching Part 1 Purpose : Determine the inverter function and operation of Q1 Procedure : Figure 1 Overall Circuit Design Figure 2 Overall Circuit setup

Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 4 From figure 1, disconnect points A and B. We are left with the circuit below. Using the circuit above, we measure the output voltage for 0V (low state) and 0.7V (high state) . We measure the voltages using the digital multimeter. Results : From the measurements we get the following: 0 V 2.53 V 0.7 V 30.78 mV Using the measurements, we can confirm that the circuit is working like an inverter. Part 2 Purpose : Determine the switching of the motor Procedure : From figure 1, reconnect point B. We are left with the circuit below. Figure 3 Inverter Circuit V O V I V I V O

Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 5 Set the distance between the motor and the hall-effect sensor to 5mm and keep the input voltage, , at 0.7V. Vary the input voltage between 0.7V and 0V and observe the powering of the motor. Results : The table below summarizes the observation. Observation 0.7V The motor is off, i.e. no movement/rotation decreasing to 0V The motor turns on and the motor speed increases 0V The motor rotates and the speed is maximum. The observation confirms that the motor power is controlled as expected. The motor is on when the input voltage is 0V and is slows down as we increase the input voltage until 0.7V when it fully turns off. Task 2: Sensor Signal Amplification and Peak Rectification for Motor Control Part 1 Purpose : Establish a 10mA constant, bias DC current through the hall-effect sensor Figure 4 Motor switching circuit V I V I

Laboratory 4  Motor Control using Semiconductor Sensor, BJTs Circuits, and Diode Rectifier 6 Procedure : Connect the hall-effect sensor connector to the circuit as shown in figure 2. (red) connects to the 1k resistor and (green) connects to ground. Remove the 100nF capacitor until the current measurement is taken. After that, put it back into the circuit as it was. To measure the current through the sensor, measure the voltage across the 1k resistor and calculate the current using Ohmʼs Law. Results : We found that the voltage across the 1k resistor is 6.44 V. So, the current across the resistor and hence, across the hall-effect sensor is  6.44 mA. This current is acceptable for DC bias current for the sensor as it is close to the required 10 mA. Part 2 Purpose : Capture the signal generated at the sensor output with the motor running Procedure : From figure 1, disconnect point C. Our goal is to measure the output signal at . Keep point A disconnected and supply 0V to the base of Q1. This will ensure the motor is on for our measurements. Place the sensor 2mm away from the rotating wheel and turn the motor on with 2.5V supply. We capture the output signals using an oscilloscope. Repeat with the sensor placed 5mm away from the rotating wheel. Results : 2mm away The capture below shows the waveform of the generated output signal. I (+) C I (−) C 1 k 6.44 V V (+) H

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