Electric timer quotation - Essay Example

Design, implement, and test a timer Summary This report contains numerous experiments conducted with an aim of assessing and ascertaining an amplifier’s performance and structure. With the knowledge of how amplifiers work, we observed the experimental results at different frequencies of oscillation. We also examined the amplifier’s sound. Using NOR gates in the experiments, our aim was to establish a time lag circuit with a 555 timer. 1.1 Introduction The experiments were based on a workplace scenario with a chemical firm requesting for an electric timer quotation. The company need a timer that could help it control chemical processes and the company already had a clue about the device that they wanted. 1.2 Aims and Objectives of the experiment The main objectives of this experiment were To build a amplifier To evaluate the performance of the built amplifier To learn the functions of its components through testing To improve my knowledge and skills of an amplifier through conducting ‘real’ experiments To strengthen my technical skill To explore the property of 555 chip through experiments To design and test a Voltage Controlled Oscillator (VCO) To build a 555-based delay unit To design and build a trigger circuit To interface the delay unit, oscillators and amplifier To calibrate the system Chapter 2: Design and test of amplifier 2.1 Introduction: An amplifier for example an audio amplifier is used to increase the amplitude of a signal that is small to a level that is useful to the user. While increasing the amplitude, the small signal’s details and characteristics are maintained. This process is known as linearly. Greater linear the more the output signal. There exists many different types of amplifiers. There has been great advancements of amplifier design in the recent past. 2.2 Equipment and component: The equipment that were used in the lab is breadboard, DC power supply (PSU) , digital MultiMeter (DMM) and oscilloscope. Furthermore, the components that were used in part 2 experiment are Resistors (Ω): 51k, 2×5.1k, 1k, 82Ω, Capacitors (nF): 470, 4.7, Transistors: BC109BP 2.3 Method and design After identification all the components the circuit was built as the figure shown below Figure 1.9: an amplifier circuit In the above circuit, all the values were as follows; R1=51k, R2=5.1k, R3=1K, R4=82R, and C1-0.47uF. Vs had a frequency of 1 kHz. ‘a’ and ‘b’ represent two nodes. 1. The value Vs was set to 0V and the voltage at the nodes was measured. 2. The magnitude of Vs was set to 0.1V. 3. The DC and AC components of the signal were measured. 4. R1 was disconnected. 5. The voltage Vb (Total) and Vb (AC). 6. R1 was reconnected. 7. C1 was disconnected and Vs was connected to the node ‘a’. 8. Vb (total) was measured and Vb (AC). 9. C1 was reconnected and R3 increased to 5.1k. The values of Vb (total) and Vb (AC) were measured. 10. The value of R3 was reset to 1k and Vs(AC ) and Vb (AC) were monitored using an oscilloscope. 11. The value of Vs was increased gradually to 0.3V. 12. To explore the effects of the input frequency, the following procedures were followed. 13. The value of Vs was reset to 0.1 V. 14. The input frequency was varied between 10 Hz and 1 MHz and for each frequency, the value of the peak b (AC) was recorded. Chapter 3: Design and test of oscillator 3.1 Aim/Objective The main objectives of conducting this lab were to Build an oscillator based on NOR gate and evaluating the performance of the oscillatoralso to know how to set the oscillating frequency and comparing the frequency with the sound 3.2 Equipment and component: in order to get an accurate outcome , all the components in table 1 should be measured . Table below shows all the materials that were used in the report Table 1. Equipment used in the lab 3.3 Method and design Figure 2.0 shows the circuit built in part 3 The chip was powered by applying 9V DC between pin 14 and pin 7 also the waveform of Va, Vb and Vc was recorded also the oscilloscope frequency was measured. To interface oscillator with the amplifier, the following was done; The oscillator was linked with the amplifier by connecting the dashed line on figure 2.0 To estimate the power delivered to the to the load, the following was done The loud speaker was replaced with the load resistor R(load)=10R The waveform of the voltage drop across the R(load) and Vload was recorded The top level of Vload, V(top) was measured To check how the power affects the amplitude of the load, the following was done The supply power was reduced from 9V gradually and the corresponding reduction Vtop value was noted To study the effect of component value on the oscillation the following was done; For the values of R=1k, 10k, 620k and 3.3M, the Vc was monitored and the frequency measured To improve the tune, the following was done. The component Reset R=100 from figure 2.0 was renamed as R4 in figure 2.1 The circuit on figure 3.2 was built on a breadboard To get the effects of the effects of the component value on the tune, values R7=620, 5.6M and 10M were used. 3.4 Results and discussion On Biasing the DC voltage using a voltmeter or oscilloscope, the voltage values can be calculated as follows Therefore the V (total) is equal to 724mV this is the value of the Peak AC Therefor the value of the peak DC is 8.60V On disconnecting the value of R1, the value of peak-to-peak voltage changes to 24mV.From this, it can be observed that this is a very large decrease and therefore R1 plays a very important role in the circuitChanging the value of R1 reduces the voltage and also the peak-to-peak value. Increasing it increases the value peak-to-peak value. Input voltage increase to 4.11V. The peak to peak value of the input also increase by 450mV.Reconnecting the resistor R1 and replacing C1 with a signal generator Disconnecting C1 means that there is a decrease of 550mV from the original input but the AC peak-to-peak value remains the same. The output signal varies from a positive to a negative value.On powering the oscillator with 9V, a saw tooth waveform is observed at the oscilloscope fo the value of Va. Vc produces a square wave with a positive amplitude while Vb produces a square waveform with a negative amplitude Frequency = 618.1Hz, theoretically, the frequency should be 1 kHz. The variation in the values of frequency are brought out by the capacitive element in the chip circuit. The total capacitance value is larger than 10nF. It can be observed that the sound of the speaker does not change. It remains constant. This shows that the oscillator is working properly. The amplifier has an input of mA and the output is in the Am region Estimating the power delivered to the load RL  There is a factor of two since this is a peak to peak power How the power affects the system V (top) starts decreasing gradually and so does the speaker. On decreasing the power supply below 3V, no sound comes from the speaker. Table 2.0 below show values for frequency obtained at different voltages Resistance (ohms) Vc (frequency) 1K 40 MHz 10K 5.6MHz 620R 100Hz 3.3 18.8Hz From the table, it is clear that the lower the value the lower the pitch of the speaker. This is as a result of varying values of the resistors. On building the circuit on figure 2.1, the tone of the speaker is heard oscillating. This means that, the larger the resistor value the slower the oscillating time. 64 ohm speaker was used because it allows more power load and is more efficient than the 8 ohm. Chapter 4: DESIGNING AND TESTING OF A DELAY UNIT 4.1 Aim/Objective The report aims to build and test of delay unit and the main objectives of the report is to explore the property of 555 chip through experiments and to design and test a Voltage Controlled Oscillator (VCO). 4.2 introduction Voltage Controlled Oscillator can be defined as a module that generates the frequency of the notes audible by human ears. This allows the user to accurately "tune and set" the pitch source. A VCO can be compared to a single string from a guitar.(Bird ,2007) 4.3 Equipment and component: The equipment that were used in the report areBreadboard, DC Power Supply Unit (PSU), Digital Multi-Meter (DMM) and Oscilloscope Furthermore, the components that were used in the lab areResistors (Ω): 330kΩ, 200k, 5×100k, 2×5.1k, 1k, 82, Capacitors (F): 10n, 22n 100μ (Tantalum), Chips: LMC555CN), LEDs: LED, Switch: On/Off Switch. 4.4 Method and design Figure 3: a 555 timer based VRO • Maximum and minimum values of V2 and Vout, and the durations were recorded. • RA was increased to 330 kΩ and observations recorded. • RA was reset to 100 kΩ and RB changed to 330kΩ and test 1 was repeated • RA was set to be equal to RB=100kΩ and the supply voltage was reduced to 6V and test 1 repeated. • The supply voltage was reduced to 3V and the test 1 was repeated • Vcc was set to 9V and a voltage of 5V was applied to pin 5. Then V5 was changed between 0 and 8 V in steps of 1V. • The minimum and maximum values of V2 and Vout together with the frequency were recorded. A graph of V2 (Maximum), V2 (Minimum), Vout (Maximum), and frequency against V5 was plotted 4.4 Results 4.5 Discussion Comparing the waveform of Vout with the waveform of Vc for the NOR gate based oscillator. It can be observed that the waveform for the 555 timer oscillator is square wave while for the NOR gate based oscillator was a triangular wave.It can also be observed that when the value of RA was increased, the amplitudes of the waves increase proportionally with respect to the increase in the value of resistance. Also the output voltage value increases proportionally from 2.8 V to 10 V. Setting RA to 100 kΩ and RB to 330kΩ. Then the duration for Vout=’high’ decreases from 2.98ms to 1.386ms while the Vout=’low’ duration remains constant. When RA was set to be equal to RB=100kΩ and the supply voltage was reduced to 6V, then theMaximum voltage= 7 V, minimum voltage= -200mV Based on the tests 3 and 4, then the relationship between the following values is as follows: • The maximum value of V2 – Vcc is inversely proportional to V2 • The minimum value of V2 - Vcc is directly proportional to V2 • The maximum value of Vout - Vcc is directly proportional to Vout. Chapter 5 PUTTING TOGETHER AND CALIBRATION 5.1 introduction An oscillator can be defined as an oscillator circuit that generates oscillating electronic signal, periodic signal or at times square waveforms or sine waveforms. They convert direct current from the source to AC signals (alternating current) any electronic devices are used for this purpose. Some conspicuous examples of signals produced by oscillators include broadcasted signals from radios and televisions, computer’s clock signals and crystal quartz clock circuits. Sounds produced by electronic beepers and from video games are also examples these signals. 5.2 COMPONENTS AND EQUIPMENT Equipment: Breadboard, DC Power Supply Unit (PSU), Battery: 9V with connectors, Digital Multi-Meter (DMM), Oscilloscope, Screwdriver Components: Resistors (O): 10k, 300k, 5×620k, Capacitors (F): 33µ, Potentiometer (O): 50k Linear Carbon, Multi-position switch Note: All resistors are of 0.25W Metal Film (: 1%) 5.3 Method 1. Interfacing The delay unit was connected to the oscillator as shown in the figure 2. Calibration a. The potentiometer was connected as shown in the figure b. For R3=620kΩ, the delay was adjusted to 60 sec 3. The circuit given in fig. 5.3 was built using a multi-position switch, and testing for the delay was done and recorded for each value of R3. 4. The power supply was replaced with a 9V battery, observations made. 5.4 RESULTS AND DISCUSSION Delay(min) 0.5 1 2 3 4 5 R3(k) 310 620 1240 1860 2480 3100 Q1:TodisabletheaboveNORgate,shouldthe‘controlsignal’be‘high’or ‘low’? (Hint:UsethelogicalpropertiesofNORgates) Answer: the control signal should be high for disabling Q2: Whatistheoutputofthedelayunit(pin3of555)beforetherequireddelayis reached? Answer: Vout=9 V 4. Q1:Whatisthefunctionof C5? 5. Answer: this capacitor is used to make sure that the system does not lose power since it will be charging and discharging at intervals 6. Q2:Whydoweusetwoswitches(S1andS2)? 7. Answer: S2 is a safety switch in that it protects the components in case of any malfunction. S1 is the systems switch for switching on and off based on status of the capacitor. Conclusion: The entire cost for all these elements that are needed can be bought from 10 pounds to 20 pounds. [10]. This is due to the fact that if the company settled on making additional units it can purchase elements in huge volumes which will cost less compared to purchasing a single item. In addition,the company is ready to pay a maximum of 50 pounds, hence they are capable of charging a better margin of product ,normally included in the unit cost. The voltage controlled oscillator was developed and tested by doing various procedures in the experiment. The properties of how different parameters change relative to others were observed in designing the VCO, and this has strengthened our practical skills on 555 timer based oscillators. Also comparison showed that the waveform for 555 timer based oscillator is rectangular in shape while that of a NOR gate-based oscillator is a triangular wave. References John Bird 2007, Electrical and Electronics Principals And Technology, third edition Newnes Elsivier UK Anil K. Maini 2007, Digital Electronics, Principle, Devices and Application, John Wiley and Son Limited, England Chi-Tsong Chen 2002, Analog and Digital Control System Design, Saunder college publishing Professor Barry Parton 1998, Fundamentals of Digital Electronics, National Instrument Corporation Read More