1. 1. Page 1 of 43 University of North Carolina at Charlotte Department of Electrical and Computer Engineering Laboratory Experimentation Report Name: Ethan Miller Date: June 19, 2014 Course Number: ECGR 3155 Section: L01 Experiment Titles: [2] Semiconductor Diodes, [3] Diodes and Bridge Rectifiers, [4] Zener Diode Voltage Regulators and Diode Clippers and Clampers Lab Partner: None Experiment Numbers: 2, 3, 4 Objectives: Experiment 2: The intention of this experiment was to examine basic circuits of I-V (Current vs. Voltage) characteristics for the use of 1N4002 and 1N5228 zener diodes. Experiment 3: The purpose of this experiment was to examine the effects of diodes, bridge rectifier circuits used in DC power supplies. Experiment 4: The purpose of this experiment was to examine the effects of zener diodes, voltage regulators, and clipper and clamper circuits used from a DC power supply. Equipment List: Items Asset # MB-106 Breadboard 00000001 10K 00000002 100F 00000003 100K 00000004 1.3K 00000005 .1F 00000006 330F 00000007 1K 00000008 510 00000009 .5 00000010 100k at 20W 00000011 1N4002 Diode 00000012 1N5228 Zener Diode 00000013 Decade Resister Box 00000014 Agilent 33509B Function Generator 00060923 Agilent InfiniiVision 2000-X Series Oscilloscope 00043982 E3612A Power Supply 00039202
2. 2. Page 2 of 43 Agilent 34461A 6 Digital Multimeter 00053024 Cadence Design System (P-Spice) 00085859 Relevant Theory/Background Information: Experiment 2: Diodes have been known for the simplest and the most fundamental nonlinear electronic element. Furthermore electronic devices are forms of a solid state microelectronic device. The following are different types of diodes leds, photodiodes, Shockley diodes, zener diodes, constant current diodes. Figures 1 and 2 have a phenomenal of the P-N junction and its electrical symbol. The diode has two junction types, P-type (doped silicon with born) and N-type (doped silicon). Also note the two types of charged carriers for current conduction are called electrons and holes. Conductivity of a semiconductor involves a wide array through the induction of a controlled quantity of impurity atoms in a semiconductor crystal process called doping. Silicon was the best element for a diode/semiconductor device to form. Silicon atoms have only 4 valence electrons, which needs to have 4 more electrons to complete the outermost shell. This was accomplished by sharing one of its valence electrons with each of its four neighboring atoms. The result of silicon was a crystal of a pure lattice structure. A convent bond was broken by thermal energy (heat) and a electron was freed. Once this electron is freed it becomes obtainable to conduct electric current, only when an electric field was applied to the crystal. As this electron departs from the atom, the atom then becomes net positive and needs another electron from a neighboring atom to become a neutral atom. Holes are formed by atoms that were net positive atoms or a positive charged carrier. As the temperature raises more covalent bonds were broken, which generates more holes and resulted in the conductivity of silicon. Current then flows from positive to negative. [1] Figure 1: Diode Figure 2: Forward Biased Diode 1N4002 V--V++
3. 3. Page 3 of 43 The positive terminal of the diode is called the anode and the negative terminal is called the cathode. A typical current-voltage curve of a diode is shown in Figure 3. This curve was divided into 3 regions. The following are the 3 regions. 1. The region in which VD > 0, called the forward-bias region 2. The region in which VD < 0, called the reverse-bias region 3. The region in which VD IZK and VZ > VZT. A voltage regulator was a circuit to provide a constant DC voltage between its output terminals.
4. 9. Page 9 of 43 This is why a zener diode was used for a voltage regulator. The output voltage is vital to remain continuous or constant in spitefulness of the following two changes that could occur (a) changes in the load current drawn from the regulator output terminals and (b) changes in DC power supply voltage that feeds to the regulator circuit. Figure 10: Zener Diode Diodes are also used for limiting the voltages and current to avoid circuit damage. In addition, to the limiting or clipping circuits voltages can vary in the development of wave- shaping circuits. Shown in Figure 11, a typical clipping circuit. In this circuit the output voltage will never be greater than 3 volts. The ideal diode becomes forward bias when the input was greater than or equal to the DC 3 volts. While clipper circuits are concerned with limiting or clipping the circuit off from the waveform, a clamper circuit is concerned with shifting the DC amplitude. The clamper circuit can be design with a capacitor, shown in Figure 12. As, the capacitor was charging, the diode clips the positive values of the input voltage. Then as the capacitor discharges and falls below zero, the diode was in reverse bias, and the input voltage shifts down by 3 volts because when the diode was in forward bias the capacitor was held at 3 volts. Thus when the diode was in reverse bias the capacitor had no effect on the voltage; there by the output voltage is -9 volts. [3] Figure 11: Diode Clipping Circuit V++ V-- 1k 3Vdc DIODE 12Vac 0
5. 10. Page 10 of 43 Figure 12: Diode Clamping Circuit Experimental Data/Analysis: Experiment 2: A half wave rectifier was constructed in P-spice and in the lab; circuit is shown in Figure 13 and P-spice graph shown in Figure 14. Setting the input voltage to 10 volts peak to peak (pk-pk), 60 Hertz (Hz), shown in Figure 15. A 10 kilo ohm load resister was connected to a 1N4002 diode, which outputted a voltage of 4.50 pk-pk shown in Figure 16. The P-Spice had an output voltage of 4.3 volts. These two graphs resulted in (P-Spice and Lab) a nominal 4.65% error found in Equation 3. The function of the diode from Figure 13 was found to be a half-wave rectifier. A half- wave rectifier was at the output, since the negative input voltage was cut off by the diode. Current cannot flow in the opposite direction of the arrow. If this would have happened the diode would be in the reverse bias region. This ensured the output voltage followed the positive amplitude of the input voltage. The amplitude of the output voltage only came to 4.5 volts because of the voltage drop across the diode. Figure 13: Half-Wave Rectifier Circuit Another circuit was constructed with a 100 micro Farad capacitor connected in parallel with the load resister shown in Figure 17. When the capacitor was place into the circuit a straight DC voltage was measured at the output shown in Figure 18. This capacitor was being charged by the input voltage. As the sinusoidal function was moving away from the 4.5 pk-pk voltage the capacitor held its voltage at the maximum value of the input voltage. The output voltage was found to be a constant 100mV pk-pk, which ensured a DC voltage output. Ideal Diode C1 0 R1 12Vac 3Vdc Dbreak D1 R1 10k 0 V1 FREQ = 60 VAMPL = 5 VOFF = 0 AC = 0
6. 11. Page 11 of 43 Figure 14: P-spice Graph of the Half-Wave Rectifier Circuit Shown in Figure 13 Figure 15: Input Voltage for Half-Wave Rectifier Circuit
7. 12. Page 12 of 43 Figure 16: Output Voltage of a Half-Wave Circuit Figure 17: Half-Wave Rectifier Capacitor Filter Circuit Dbreak D1 R1 10k C1 100uF V1 FREQ = 60Hz VAMPL = 5 VOFF = 0 AC = 0 0
8. 13. Page 13 of 43 Figure 18: Output Voltage of a Half-Wave Rectifier Capacitor Filter Figure 19: Ripple Voltage of the Half-Wave Rectifier Capacitor Filter Circuit
9. 14. Page 14 of 43 The DC coupling was selected on the oscilloscope to take a closer look at the DC voltage. Found in Figure 19 was a waveform of the ripple voltage due to the capacitor. This happened because the capacitor discharged from the maximum input voltage. As the sinusoidal waveform started to increase and reaches the same output voltage as the capacitor, the capacitor then started to charge again to the maximum input voltage. Figure 20: Diode Resister Logic Circuit (And Gate) Figure 21: Diode Resister Logic Circuit (Or Gate) Dbreak D1 R1 1k V1 5Vdc Dbreak D2 0 Input # 1 Input # 2 Dbreak D1 R1 1k V1 5Vdc Dbreak D2 0 Input # 1 Input # 2
10. 15. Page 15 of 43 Diode resister logic circuits were constructed and are shown in Figures 20 and 21. A 5 volts DC supply was applied to determine which logic gate by the use of 1N4002 diodes. Each diode had a different input voltage found in Tables 1 and 2, to determine the output voltage of the circuit. The output voltage was measured across the load resister of 1k. A nominal value of 5.06 volts was found across the output only when diodes 1 and 2 were connected to logical 1 high (positive 5 volts) shown in Table 1. Input voltage # 1 was the positive voltage (logical 1) and input voltage # 2 was the ground (logical 0) or 0 volts. To ensure there was an output voltage across the load resister the diode needed to have current. For the diode to have current flowing, a voltage at the output needed to be higher than the voltage of the negative terminal of the diode. The diode logic and gate was found by the input voltage logical 1.The two diodes were in reverse bias when both inputs were connected to logical 1. Thus the diode was found to have an output logical 1 because there was no current flowing through the diode. As the input was logical 0, the diode then conducted in forward bias which was found to have current through the diode. Hence a 0 voltage output across the load resister or as showed in the Table 1 650mV (very close to 0 volts). A nominal value of 4.69 volts was found across the output when diodes 1 and 2 were connected to logical 1 high (positive 5 volts) or logical 0 low (ground 0 volts) shown in Table 2. The output voltage did not outputted 4.69 volts when both of the diodes were connected to logical 0 low. The two diodes were found to be in forward bias when the input voltage was connected to high, which had a current through the diodes and created a voltage drop across the load resister. As the input was logical 0 across both diodes, the diode was then in reverse bias. Hence a 0 voltage output across the load resister or as showed in the Table 2 650mV (very close to 0 volts). Table 1: And Gate Diode Resister Logic Connect Terminal D1 D2 Output Voltage to terminal Input # 2 Input # 2 0-650mVolts to terminal Input # 2 Input # 1 0-650mVolts to terminal Input # 1 Input # 2 0-650mVolts to terminal Input # 1 Input # 1 5.06Volts Table 2: Or Gate Diode Resister Logic Connect Terminal D1 D2 Output Voltage to terminal Input # 2 Input # 2 0-650mVolts to terminal Input # 2 Input # 1 4.69 Volts to terminal Input # 1 Input # 2 4.69 Volts to terminal Input # 1 Input # 1 4.69 Volts
11. 16. Page 16 of 43 A zener diode voltage regulator circuit was constructed shown in Figure 22. To demonstrate the voltage regulation for the circuit a 12 volts DC, a 100 ohm 20 watt resister and a variable load resister was applied. Table 3 shows the output voltage as the load resister was changed from 1k ohms to 2 ohms. This zener diode circuit held a constant voltage at the output for a desired value. This desired value was found to be 4.16 volts. A zener diode was put in reverse bias region to ensure the current across the zener was IZ and the voltage was VZ. These two values needed to hold the voltage output at 4.16 volts. As the load resister was changing from ohms to ohms the load current was changing. This current cannot be greater than IZ. When the load current was greater than IZ the zener diode was in breakdown region. Thus the output voltage was much lower than the constant output nominal voltage of 4.16. Table 3: Zener Diode Voltage Regulator Resister Value Output Voltage Resister Value Output Voltage 1k 4.25 200 4.08 900 4.21 100 4 800 4.16 50 3.6 700 4.16 20 2.04 600 4.16 10 1.15 500 4.16 5 0.641 400 4.17 3 0.42 300 4.12 2 0.308 Figure 22: Zener Diode Voltage Regulator Circuit R1 100 V1 12Vdc 0 Dbreak D1 R2 1k
12. 17. Page 17 of 43 A zener diode clipper circuit was constructed shown in Figure 23. To express the clipper circuit a 20 volt pk-pk sinusoidal input at 1k Hz, 1k ohm and a two zener diodes was applied. The zener diode circuit held a constant output voltage of 8.4 pk-pk. As shown in Figure 25 the zener diodes cut-off the sinusoidal input waveform at the positive and negative cycles. In the positive sinusoidal cycle the zener diode clipped (D1) the input waveform due to the voltage across the zener diode and a similar effect appeared in the negative cycle (D2) of the sinusoidal waveform. Applications of a clipped circuit involve converting an AC waveform to DC waveform, and mostly to ensure the output voltage never exceeds a certain level protecting the existing circuit from voltage spikes. [4] Figure 23: Zener Diode Clipper Circuit Figure 24: Input Voltage Zener Diode Clipper Circuit R1 1k 0 Dbreak D1 Dbreak D2 V1 FREQ = 1k VAMPL = 10 VOFF = 0 AC = 0
13. 18. Page 18 of 43 Figure 25: Output Voltage Zener Diode Clipper Circuit Laboratory Computation (Eqn. 3)
14. 19. Page 19 of 43 Experiment 3: A full-wave and a half-wave rectifier circuit were constructed in the lab, shown in Figure 26. The half-wave rectifier circuit was constructed in the same manner as the full- wave circuit, but with one of the diodes blown. A 120 volts AC was applied to the transformer which had a 10 to 1 ratio. Four 1N4002 diodes were used to build the full- wave rectifier with a load resister of 510 ohms along with a capacitor and .5 ohms in parallel. The use of 1N4002 was selected since the PIV rating was 400 volts found on the datasheet. The input voltage was found to have 36.2 volts pk to pk and 12.967 volts, shown in Figure 27. Verification of the half-wave and full-wave rectifier circuits are shown in Figures 28 and 29. Figure 26: Filtered Full Wave Bridge Rectifier Circuit Figure 27: Input Voltage before the Diode Bridge 10:1 120Vac RMS - + 2 1 3 4 C 330uF RS .5 RL 510
15. 20. Page 20 of 43 Figure 28: Output Waveform for Full-Wave Rectifier Circuit Figure 29: Output Waveform for the Half-Wave Rectifier Circuit
16. 21. Page 21 of 43 Figure 30: Full-Wave Rectifier Output Ripple Voltage Figure 31: Half-Wave Rectifier Output Ripple Voltage
17. 22. Page 22 of 43 Measurements were then taken from the oscilloscope. These measurements are found in the following Figures and the calculated measured results are found in the laboratory computation list. Shown in Tables 3 and 4 are the percent error difference from the pre-lab and measured calculations. Table 4: Full-Wave Rectifier Percent Errors Item Calculated Value Calculated Measured Value Percent Error Ripple Frequency 120 121.22 1.016666667 Peak Output Voltage 14.1705 14.518 2.452277619 Pk to Pk Ripple Voltage 0.70165 0.71416 1.782940212 Load Current 0.0277 0.02839 2.490974729 Diode Average Current 0.30424 0.31274 2.793846963 Diode Maximum Current 0.58078 0.59715 2.818623231 Figure 32: Capacitor Charge Time for the Full-Wave Rectifier
18. 23. Page 23 of 43 Table 5: Half-Wave Rectifier Percent Errors Item Calculated Value Calculated Measured Value Percent Error Ripple Frequency 60 59.975 0.041666667 Peak Output Voltage 15.5705 14.778 5.089753059 Pk to Pk Ripple Voltage 1.541 1.4693 4.652822842 Load Current 0.0305 0.0289 5.245901639 Diode Average Current 0.2458 0.2325 5.410903173 Diode Maximum Current 0.4609 0.4361 5.380776741 The results from the percent error calculations shown in Tables 4 and 5. The full-wave rectifier had little or none percent error compared to the half-wave rectifier circuit. The full-wave rectifier circuit resulted satisfactory data results because of the little percent error. A 2 percent error could have resulted in some minor sig-fig from the calculations, and possibly a resistance factor in the wires, which could have resulted in a different resister value. The half-wave rectifier circuit resulted around 5 percent error. This error cloud have resulted in a similar fashion as the full-wave rectifier but the diode drop of 1N4002 may have changed due to the mistake of not putting the oscilloscope in AC coupling for the different measurements. There different methods were calculated to determine the load current, this is shown in Equations 12, 13, 14 for the full-wave rectifier and 22, 23, 24 for the half-wave rectifier circuit. The resulted load current values did not come near the calculated load current for both rectifier circuits. The slope method was the least accurate because of the resulting values of the change in charging and discharging of time could have been wrong do to the accuracy of the oscilloscope. Also, during the charging and discharging times of the capacitor the diode was either on or off. These changing in voltages and times cloud have been greater affected by the end calculated result. Even though these changes are small compared to the overall voltage at the output, the diode was still changing in the voltage. This cloud greater affected the overall current. The average load current calculated was the most accurate result in both rectifiers. The average value of the load current took into count of the full sinusoidal waveform (all instantaneous values taken under the curve) as the rms value took only the DC voltage into count. The rms value only took into count half of the sinusoidal cycle. Either voltage measurements were great to use but in this lab the average value resulted in a better accuracy of voltage.
19. 24. Page 24 of 43 Figure 33: Capacitor Discharge Time for the Full-Wave Rectifier Figure 34: Capacitor Charge Time for the Half-Wave Rectifier
20. 25. Page 25 of 43 Figure 35: Capacitor Discharge Time for Half-Wave Rectifier Figure 36: Output Voltage of Full-Wave Rectifier across Rs
21. 26. Page 26 of 43 Figure 37: Output Voltage of Half-Wave Rectifier across Rs Figure 38: Output Ripple Voltage of Full-Wave Rectifier across RL
22. 27. Page 27 of 43 Shown in Figures 39, 40 and 41 are graphs of the load current at across the load resister, the capacitor and the diode. The load resister was found to have a constant voltage because of the capacitor across the load. The capacitor kept the output at a steady voltage. Figure 39 shows the capacitor current, the capacitor had little or no current at all. This capacitor was design to hold the voltage across the load as the input voltage was sinusoidal. Figure 40 shows how the diode was on (had current flowing) and off (had voltage and no current). Figure 38: Output Ripple Voltage of Half-Wave Rectifier across RL 0 5 10 15 20 25 30 0 2 4 6 8 10 12 LoadCurrent(milliamps) Time (milliseconds) Load Current Across RL Load Current Load Current Across RL ECGR 3155 Systems and Electronics Lab Experiment #3 Diodes and Bridge Rectifiers Ethan Miller Figure 39: Load Current across RL Full-Wave Rectifier
23. 28. Page 28 of 43 y = 200.23e-5087x 0 50 100 150 200 250 0 0.005 0.01 0.015 0.02 0.025 CapacitorCurrent(amps) Time (seconds) Capacitor Current Capaciter Current Expon. (Capaciter Current) Capacitor Current ECGR 3155-Systems and Electronics Lab Experiment #3 Diodes and Bridge Rectifiers Figure 40: Capacitor Current Full-Wave Rectifier Across RS
24. 29. Page 29 of 43 0 1 2 3 4 5 6 7 8 9 0 2 4 6 8 10 12 DiodeLoadCurrent(amps) Time (milliseconds) Diode Load Current Diode Load Current Diode Load Current ECGR 3155 Systems and Electronics Lab Experiment #3 Diodes and Bridge Rectifiers Ethan Miller Figure 41: Diode Current Full-Wave Rectifier
25. 30. Page 30 of 43 Laboratory Computation Full-Wave Rectifier Circuit (Eqn.4) 3.82 Volts (Eqn.5) (Eqn.6) (Eqn.7) (Eqn.8) (Eqn.9) (Eqn.10) (Eqn.11) (Eqn.12) (Eqn.13) (Eqn.14)
26. 31. Page 31 of 43 Half-Wave Rectifier Circuit (Eqn.15) (Eqn.16) (Eqn.17) (Eqn.18) (Eqn.19) (Eqn.20) (Eqn.21) (Eqn.22) (Eqn.23) (Eqn.24)
27. 32. Page 32 of 43 Experiment 4: A voltage regulator circuit was constructed in the lab, shown in Figure 42.A verification of its operation was observed by the output voltage on the oscilloscope while the load resister was changed in order to achieve 5mA, 2.5mA and 0mA. Shown in Table 6 was the data collected during the lab. An output ripple voltage was observed during the lab. The ripple voltage was caused from the power supply internal components of a bridge rectifier shown in Figure 26. From the data collected the output voltage dropped below the design value of 13 volts with a max load current of 5mA. As the load current was higher than the load current the voltage dropped to 7.55 volts. This was caused by the diode characteristics shown in Figure 3. A zener diode was connected in reverse bias; this means the diode was in the breakdown region. The zener diode had a maximum current to hold a constant voltage across RL. When this limit was reached the voltage dropped because of the breakdown region. The breakdown region of the zener was reached by the breakdown voltage called VZ. Figure 42: Voltage Regulator Circuit Table 6: Voltage Regulator Circuit RS 1300 RL20Vdc DIODE ZENER Measured Value (ohms) Current (milliamps) Resistor Value (ohms) Voltage of Load (Volts) RS 1.283K 5mA 2.6K 13.4 V RL 2.562K 2.5mA 5.2K 16V Ripple Voltage (millivolts) 0mA 0 20V 3.4mV pk-pk 10mA 783.282 7.55V
28. 33. Page 33 of 43 Three circuits were built to demonstrate a clipper circuit, shown in Figures 43, 44 and 45. The input voltage and the output voltages were taken from the oscilloscope to verify the operation of a clipper circuit. Also shown in Figures 48 and 51 were the P-Spice values of the following diode clipper circuits. Figure 43: Diode Clipper Circuit Figure 44: Diode Clipper Circuit #1 Figure 45: Diode Clipper Circuit #2 1K D1 3Vdc FREQ = 1K VAMPL = 6V VOFF = 0 AC = 1 1K D1 4Vdc FREQ = 1K VAMPL = 6V VOFF = 0 AC = 1 0 1K D1 -4Vdc FREQ = 1K VAMPL = 6V VOFF = 0 AC = 1 0
29. 34. Page 34 of 43 Figure 46: Input Voltage Diode Clipper Circuits Figure 47: Output Voltage Diode Clipper Circuit
30. 35. Page 35 of 43 Figure 49: Output Voltage Diode Clipper Circuit #1 Figure 48: P-Spice Output Voltage Diode Clipper Circuit #1
31. 36. Page 36 of 43 Figure 50: Output Voltage Diode Clipper Circuit #2 Figure 51: P-Spice Output Voltage Diode Clipper Circuit #2
32. 37. Page 37 of 43 From the data collected the clipper circuits did work as expected from P-spice. The effects of using a non-ideal diode were found to have a forward voltage drop of more than .7 volts. The 1N4002 had a diode drop approximately to 1.1 volts. Ideal diodes would have had a characteristic curve shown in Figure 3. There would have been no forward voltage and the ideal diode would have been in the on position at 0 volts. Since there was a power supply after the resistor shifted the graph either down by 4 volts or up by 4 volts. Normally a diode resister circuit starts at the origin shown in Figure 14. Since the power supply was connected in series with the diode and resistor, the power supply acted resembled a ground to the circuit. Three circuits were built to demonstrate a clamper circuit, shown in Figures 52, 53, and 54. The input voltage and the output voltages were taken from the oscilloscope to verify the operation of a clamper circuit. Also shown in Figures 57 and 59 were the P-Spice values of the following diode clamper circuits. Figure 52: Diode Clamper Circuit Figure 53: Diode Clamper Circuit #1 Figure 54: Diode Clamper Circuit #2 D1 3Vdc 0 C1 .1uF R1 100K TD = 0 TF = 0 PW = 1us PER = 2.25us V1 = -6 TR = 0 V2 = 6 C1 .1uF R1 100k V2 -3Vdc Dbreak D1 0 V3 TD = 0 TF = 0 PW = 1us PER = 2.25us V1 = -6 TR = 0 V2 = 6 D1 9Vdc 0 C1 .1uF R1 100K TD = 0 TF = 0 PW = 1us PER = 2.25us V1 = -6 TR = 0 V2 = 6
33. 38. Page 38 of 43 Figure 55: Input Voltage Diode Clamper Circuit Figure 56: Output Voltage Diode Clamper Circuit
34. 39. Page 39 of 43 Figure 57: P-Spice Output Voltage Diode Clamper Circuit #1 Figure 58: Output Voltage Diode Clamper Circuit #1
35. 40. Page 40 of 43 Figure 59: P-Spice Output Voltage Diode Clamper Circuit #2 Figure 60: Output Voltage Diode Clamper Circuit #2
36. 41. Page 41 of 43 The clamper circuit worked as expected in the lab. The effect of the pulse width much smaller than time constant of the circuit resulted in a charge or discharge in the output voltage of the circuit, shown in the output Figures of the clamper circuit. Some of the complications that were anticipated when using the output voltages as a circuit to drive a low impedance clock are the trigging edge of the waveform. If the clock was the input a preceding circuit the trigging edge of the clock would jumble up the preceding circuit and would not count correct. If this clock was connected to a low impedance circuit, the input clock would dramatically change the input current of the preceding circuit. Generally preceding circuit should have a high input impedance to have the same current thought out the circuit. Laboratory Computation
37. 42. Page 42 of 43 Conclusions: Experiment 2: In conclusion the following circuits were experimented in the lab DC voltage output, diode logic, zener diodes, and clipped circuits. Clipped circuits were design to cut-off a certain value from the sinusoidal input voltage. These circuits protected the next stage from voltage spikes and power consumption. An example of these circuits was found to be the two zener diodes, and a diode resister circuit. A zener diode was connected in series with a variable resister. This was found to be a voltage regulator. This regulator held a constant voltage across the load resister as long as the load current was not greater than the current across the zener diode. A DC voltage was obtained from a diode resister with a capacitor connected across the load. The capacitor held a constant charge from the sinusoidal input voltage waveform. Diode logic circuits were found to be either an or gate or an and gate. The circuit shown in Figure 21 resembled an or gate when either diode was applied a logical 1 to the input, which the output then exhibit a voltage across the load resister. The circuit shown in Figure 22 resembled an and gate when both input voltages were logical 1, which the output then exhibit a voltage across the load resister. Experiment 3: In conclusion the half-wave and full-wave rectifier was experiment in the lab. The ripple frequency, peak output voltage, peak to peak ripple voltage, load current, diode average current and diode maximum current had sufficient results compared to the calculated values. Both full-wave and half-wave rectifiers had adequate percent errors. Although the half-wave rectifier resulted in about 4 to 5 percent error. Three methods were then calculated for an output current value. These methods include the following the average current, slope of the current due to the ripple voltage and current across the sensing resister Rs. The slope method was the least effective current because of the extreme changes in the load voltage. The most accurate method was found to be the average current across the load.
38. 43. Page 43 of 43 Experiment 4: In conclusion the clipper, clamper and a voltage regulator circuits were experimented in the lab. The voltage regulator was measured for a ripple voltage and different resisters were found to establish a constant output voltage. A current of 10mA was found to have dropped the output voltage. The low outputted voltage resulted I breakdown region of the zener diode. Three circuits of a clamper and clipper were then observed during the lab. As results the clipper circuits clipped a part of the input voltage according to the direction of the diode. The Clamper circuit clipped a part of the input voltage and shifted the DC output voltage according to how the circuit was configured. List of Attachments: 1N4002 Datasheet 1N5228 Datasheet References: [2] Lab Handout Semiconductor Diodes [3] Lab Handout Diodes and Bridge Rectifiers [4] Lab Handout Zener Diode Voltage Regulators and Diode Clippers and Clampers This report was submitted in compliance with UNCC POLICY STATEMENT #105 THE CODE OF STUDENT ACADEMIC INTEGRITY, Revised August 24, 2008 (http://www.legal.uncc.edu/policies/ps-105.html) (ECM). [1] A. S. Sedra and K. C. Smith, Microelectronics Circuits, sixth ed., New York: Oxford University Press, 2010. [2] K. Bigelow, "Diode Logic," Play-Hookey, 6 June 2014. [Online]. Available: http://www.play-hookey.com/digital_electronics/dl_gates.html. [Accessed 7 June 2014]. [3] E. Project, "Power Supply For Intergrated Circuit," ElectronicsTutorials, 12 May 2014. [Online]. Available: http://electronicsproject.org/power-supply-for-integrated-circuit- ics-and-microprocessor/. [Accessed 3 June 2014]. [4] W. Storr, "The Average Voltage of a Sinusoid," Electronics Tutorials, 11 June 2014. [Online]. Available: http://www.electronics-tutorials.ws/accircuits/average-voltage.html. [Accessed 13 June 2014].