Mohammad Aqeil 0061012769 ELE1502 ASSIGNMENT 2Circuit 1: Power Supply Development Analysis: Range of output voltage It is given that: Power Supply Plug is providing the voltage of 14 VAC and the value of capacitor 𝐱 is 100 uF. Potentiometer connected to the LM317 can vary its resistance from 0 k to 10 k. So, when potentiometer resistance is = 0 k, the voltage is calculated as; 𝐵𝐵 = 𝐵𝐵 (1 + 0𝐠1.+ 2𝐠5𝐩 + 𝐵𝐵(5𝐩 For LM317, 𝐵𝐵 = 1.25 V and 𝐵𝐵 = 50 uA 𝐵𝐵 = 1.25 (1 + 0𝐠1.+ 2𝐠5𝐩 + 50𝐨5𝐩 = 6.46 + 0.25 = 6.71 𝐍 And when potentiometer resistance is = 10 k, the voltage is calculated as; 𝐵𝐵 = 𝐵𝐵 (1 + 101 𝐮2 + 𝐵𝐩 + 𝐵𝐵(15𝐩 𝐵𝐵 = 1.25 (1 + 1 15 .2𝐠𝐩 + 50𝐨15𝐩 = 16.88 + 0.75 = 17.63 𝐍 So, maximum possible achievable output voltage after the adjustment of potentiometer connected with LM317 is from 6.71 V to 17.63 V.Further Analysis for suitability of Capacitor 𝐵: The following data is obtained to validate the suitability of the capacitor 𝐱; Potentiometer Setting Value of Capacitor 𝐵 Output Voltage Ripple Voltage 0 k 100 uF 6.71 V 0V 10 k 100 uF 12V to 16V 4V 0 k 470 uF 6.71 V 0V 10 k 470 uF 15.2 V to 16.0V 0.8 V Table 1 When potentiometer is set to 0 k, the output voltage is exactly 6.71 V without any ripple for 𝐱 as 100 uF. So we can say that this value of the capacitor is suitable for this output voltage. When potentiometer is set to 10 k, the output voltage is fluctuating between 12V to 16V for 𝐱 as 100 uF. So, we are having ripple voltage of 4V. So it is concluded that 𝐱 = 100 uF is not suitable choice when potentiometer is set to 10 k. The value of ripple voltage can be reduced by increasing the value of the capacitor 𝐱. The same analysis is repeated for 𝐱 = 470 uF, it is clear from the table 1 that the output ripple voltage is reduced from 4V to 0.8V .Building and Testing: The circuit is implemented on breadboard as shown below and measurements are taken by the DMM. Fig 1Part a: Potentiometer Setting 𝐵 Current Output Input Measured Voltage Output Measured Voltage 0 k 100 uF 0 mA 14 VAC 7.19 V 0 k 100 uF 100 mA 14 VAC 6.89V to 7.19 V 10 k 100 uF 0 mA 14 VAC 12.13 V to 16.2 V 10 k 100 uF 100 mA 14 VAC 8.0V to 16.0 V Table 2 Part b: Potentiometer Setting 𝐵 Current Output Output Measured Voltage Ripple V Measured oltage 0 k 100 uF 0 mA 7.19 V 0 V 0 k 100 uF 100 mA 6.89V to 7.19 V 0.16 V 10 k 100 uF 0 mA 12.13 V to 16.2 V 3.8 V 10 k 100 uF 100 mA 8.0V to 16.0 V 8 V Table 2 Part c: Observation: It is clear from Part (a) and Part (b) that as the output current and output voltage increases the amount of ripple voltage increases. Recommendation: To reduce the output ripple voltage, the first we need to increase the value of capacitor 𝐱. The following data is obtained by selecting the value of 𝐱 = 470 uF.Potentiometer Setting 𝐵 Current Output Output Measured Voltage Ripple V Measured oltage 0 k 470 uF 0 mA 7.19 V 0 V 0 k 470 uF 100 mA 7.19 V 0 V 10 k 470 uF 0 mA 15.2 V to 16.2 V 1 V 10 k 470 uF 100 mA 13.6 V to 16.1 V 2.5 V Table 3 Verification: By comparing Table 2 and Table 3 it can be concluded that when capacitor 𝐱 value is increased from 100uF to 470uF the ripple voltage is considerably reduced. This ripple voltage can further be reduces by increasing more the value of capacitor 𝐱. Complete Circuit Diagram: The complete circuit diagram with modified value of capacitor is shown belowCircuit 2: Sample and Hold Peak Detector Circuit Analysis: Calculating Expected Voltages at A and B Points As 𝐵𝐠= 12𝐬 which is applied to all the active components 555 timer, 741 op amp and LM339 op amp. When switch SW is closed momentarily, the voltage at point A and B is given by the following expression. 𝐵 = (𝐵10 + 𝐠10𝐩 𝐠𝐵 𝐵 = 𝐠𝐠− 𝐵 = 𝐠𝐠− 0.7 When 𝐵 = 100  = 0.1 k 𝐵 = (0.1𝐠10 +𝐱0𝐩 12 = (10 10 .1 𝐵) 12 ≅ 11.88 𝐍 𝐵 = 𝐠𝐠− 0.7 = 11.88 − 0.7 = 11.22𝐍 When 𝐵 = 5.6 𝑗 𝐵 = (5.6𝐠10 +𝐱0𝐩 12 = (15 10 .6 𝐵) 12 ≅ 7.70 𝐍 𝐵 = 𝐠𝐠− 0.7 = 7.70 − 0.7 = 7𝐍 When 𝐵 = 33 𝑗 𝐵 = (33𝐱0 +𝐠10𝐩 12 = (10 43𝐠𝐩 12 ≅ 2.79 𝐍 𝐵 = 𝐠𝐠− 0.7 = 2.79 − 0.7 = 2.09 𝐍 Determining the expected timing at the output of 555 timer, 741 and 339 Width of the 555 timer output is calculated for the given circuit is calculated using the following formula;𝐍 𝐵𝐵𝐠= 1.1 × 100𝐠× 0.22𝐠= 24.2 𝐵 When momentary switch is pressed, the 555 timer has positive output, the diode becomes forward biased and the capacitor is charged to the voltage 𝐠𝐠− 0.7. Now 741 op amp is connected in non-inverting mode with unity feedback, so the input voltage (𝐠𝐠− 0.7) of 741 op amp becomes equal to the output voltage 𝐵. Now as switch is opened and the diode is reverse biased. So the capacitor starts discharging, and hence 𝐵 also starts decreasing. Discharging Time Constant of 741 op-amp circuit is calculated as; 𝐵𝐵𝔎𝐵𝐵741 = 220𝐠× 100𝐠= 22 𝐍 So, 𝐵 decreases to its 63.6% value in 22 seconds. LM339 is working as comparator, its negative terminal is fixed at 3.41 using the resistor divider network. When value of 𝐵 is more than 3.41 V, LM339 has the output voltage of 12V, while when 𝐵 become less than 3.41 V the output of LM339 reduces to zero and Green LED turns ON. So from above discussion the following table is obtained. Value of Capacitor 𝐠Resistance Time Constant Discharging 10 uF 220 k 2.2 s 100 uF 220 k 22 s Table 4The waveforms are; Fig 3Building and Testing: The circuit is implemented on breadboard as shown below and measurements are taken by the DMM. Fig 4Part a: Detecting the Peak Voltage at A and B using DMM Resistance Value 𝐵 𝐵 𝐵 100  11.88 V 11.22 V 5.6 k 7.70 V 7.0 V 33 k 2.79 V 2.0 V Table 5 Part b: Detecting the Peak Voltage at A and B using DMM Capacitor 𝐠Time Taken by Green LED to change its state 10 uF 2.5 sec 100 uF 25.5 sec Table 6 Part c: Observations and Recommendations From Part (a) and (b) the following observations are made and accordingly recommendation is suggested. 1. As value of 𝐵 resistance is increased, the voltage at point A and B decreases and hence the time required to change the state of Green LED decreases. To make the circuit operation faster minimum value of 𝐵 should be made zero. 2. As the value of capacitor 𝐠is reduces, the discharging time constant of 741 op amp reduces and hence voltage at point B reduces at faster rate and hence the time required to change the state of Green LED reduces. Hence to make the circuit operation faster minimum value of 𝐠is desirable and vice versa. The complete circuit diagram is given below.Fig 5