eeng1910-final mini project report 12-31-13 - about...

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Final Mini Project Report

Integrated System Analysis Team 1

Savath Lieng: Leader Jose Diaz: Certifier

Shabuktagin Photon Khan: Rapporteur

Abstract This mini project III shows an integrated system analysis. In this project, we built and integrated four independent circuits – two analog and two digital circuits. For these circuits, we used four independent integrated circuit chipsets – 4017 Decade Counter, 4049 Hex Inverter, LS272 Dual Op Amp, and LM324 Quad Op Amp. This report shows an analysis on these circuits and focuses on a system without feedback, which is divided into three components: input, processing and output. Introduction We can think of electronic “systems”, such as ambulance, siren or other sound machines, the principles of which can be applied to the devices that are built with 4017 Decade Counter, 4049 Hex Inverter, LS272 Dual Op Amp and LM324 Quad Amp. The speaker that was used in the circuit received audible output from the sensitive audio oscillator and Op amp tone mixer. The LEDs were used for visual output for the Switch Bound Analyzer. The LEDs and the speaker were used as outputs for the bar graph readouts. Report A system is a set of connected parts forming a complex entire circuit or device. In engineering, a system without feedback is divided into three components – input, processing and output, as shown in Figure 1 (represented by a universal I-P-O “processing circuit diagram).

Figure 1: Generic block diagram of a “system”

Input Processing Output

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Figure 2: Light – Sensitive Audio Oscillator Figure 2 is a sensitive audio oscillator. This circuit consists of a TLC272 IC that has a precision dual operational amplifier, combined with a wide range of input offset voltage grades of low offset voltage drift, high input impedance and low noise. There are also four resistors (R1-47k, R2-10k, R3-1M, R4-100k) and a C1-.1UF capacitor in this circuit. The TLC272 can operate well when powered by only 3 volts. The transformer with speaker can be used to provide sounds without using any power amplifiers. Thus, when the power switch is on, a tone with few hundreds hertz is heard by placing a finger over the photo resistor. The frequency of the tone rises to few thousand hertz when we move our finger away from the resistor. Next, we modified the circuit by replacing the transformer with a LM386 power amplifier. The R3 was replaced with 1M console pot to make an adjustable circuit. Analysis: Light – Sensitive Audio Oscillator This oscillator was sensitive to the variations in light conditions. After completing the circuit, at first, the noise coming out of the speakers had a really high pitch. The circuit was oscillating at a high frequency when the input light was very bright. In order to test this light sensitivity response theory, we covered the photo resister so that no light could enter it. With no light passing through the resister, the sound became a lot deeper as the circuit started oscillating at a much lower frequency. A flashlight was used on the photo resistor to analyze the variation in the intensity of the LED light at the output. We concluded that the brightness of the LED decreases as the distance of the flashlight beam focused on the photo resistor increases.

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Figure 3: Op Amp Tone Mixer Figure 3 is an Op Amp Tone Mixer. This consists of a 324 IC, which has four independent high-gain frequency-compensated operational amplifiers that are designed specifically to operate from a single supply over a wide range of voltages. There are also eight resistors and two capacitors in this circuit. When the power switch is on, it either outputs a continuous or pulsating tone. By adjusting the 100k and 10k console pots (R1 and R3), the output can be a mix of tones and pulses. Analysis: Op Amp Tone Mixer Even though this circuit seems very similar to the first circuit we built, this definitely has some unique characteristics. Instead of the earlier audio oscillator, we used a console pot (a spinning wheel) in this circuit. The sound at the output fluctuates as the wheel is turned a certain way. In conclusion, we determined that when the wheel was turned clockwise, the frequency became lower and lower until the wheel could no longer be turned. On the other hand, when the wheel was turned counter-clockwise, the sound turned into a higher pitch, as the frequency of the sound became higher.

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Figure 4: Switch Bounce Analyzer Analysis: Switch Bounce Analyzer Figure 4 is a switch bouncer analyzer. When the switch of the electronic circuit was turned on, switch S2 was enabled. This made the LED 1 glow. When switch S1 was pressed and released in order to create a single pulse to the 4017, the LED 2 was lit. At any time when the switch S2 is pressed, the counter was reset.

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Figure 5: Bar Graph Readout Analysis: Bar Graph Readout Figure 5 displays a readout of the bar graph generated by the circuits. After the switch was turned on, the 1M console and pot (R1) were adjusted until some of the LEDs lit up. Then the 10k console pot was adjusted at different resistances. The resistance R1 was also adjusted until all the 10 LEDs lit up. The speaker emitted a pulsating buzz or tone since all of the ten LEDs were connected to the speaker. The tone stopped when the LEDs were turned off. The resistance R3 controlled the bar graph flash rate and the pulsating tones. Calculations The RC time constant of an RC circuit is a time constant (seconds) which is equal to the product of the circuit resistance (in ohms) and the circuit capacitance (in farads). Mathematically, it is written as = R * C. The time constant is the time required for the capacitor to be charged through the resistor, by ≈ 63.2 percent of the difference between the initial value and final value, or discharged to ≈36.8 percent. The frequency f is given by: f =1/ = 1/RC ……………………………………………………..................Equation 1

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Multisim

Figure 6: Multisim for Light – Sensitive Audio Oscillator

Figure 7: Graph for Light – Sensitive Audio Oscillator

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Figure 8: Multisim for Op AMP Tone Mixer

Figure 9: Graph for Op AMP Tone Mixer

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Figure 10: Multisim for Switch Bounce Analyzer

Figure 11: Bar Graph Readout

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Problems Encountered Identifying the correct resistances of the resisters was very tedious. After recognizing and labeling the correct resistances, it only took a few minutes to match with the resistance color code chart. We also encountered some erroneous results when the capacitors were connected with the wrong polarity. Once the capacitors were connected properly, this problem was resolved. Team Building Working on these mini projects in this class was definitely a learning curve for all of us. Unlike other teams, this was the first project we worked together as a team since we worked with different team members in the first two mini projects. It was definitely a challenge to determine the strengths and weaknesses of each member in such a time constraint. However, we overcame these challenges by effectively communicating with each other and successfully presented our final project. Applications The integrated circuit chipsets used in this circuit has various practical real world applications. The 4017 Decade counter is an extremely useful device for project work and is used in the Games Timer and in construction kits including the Light Chaser and the Matrix Die. The 4049 Hex Inverter is used in current drivers, or logic-level conversion applications. The LM324 Quad Amp IC application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits, which can be easily implemented in single power supply systems. Conclusion The four circuits were used to demonstrate the three components of a small system. The system allowed us to understand the variation in output with respect to changing input signals. In all the circuits in this project, the output was altered using potentiometers. We illustrated the basic components of the IPO system by using different inputs (I) and outputs (O). We also learned about effective time management by applying the Gantt chart and key result areas. References [1] Mims III, F.M., “Basic Electronics Workbook I,” RadioShack, Fort Worth, TX. [2] http://www.ni.com/multisim/ [3] http://www.ti.com/product/lm324-‐n

eeng1910-final mini project report 12-31-13 - about...

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