Microphone Amplifier - Report Example

Running Head: 360663 Microphone Amplifier Report 360663 Microphone Amplifier Report Insert Name: Tutor: Abstract This is a report on the design and manufacture of a portable microphone amplifier for use in the media industry. It is delivered as part fulfillment of BEng (HONS) Electronic engineering degree programme. The design circuit that has been used can equally be used as an interface between the microphone and the broadcast media sound output system. In a smaller way the same design could be implemented in normal home stereo amplifications for any sound input whether from Compact disk (CD), auxiliary sound inputs or tape inputs or even public address systems in large amphitheaters or lecturer hall in college. Introduction The final product consists of basic amplifier, preamplification circuitry integrated and a filtering to achieve the right quality of sound output. The completed project is product mounted in a protective enclosure, which will allow the product to be portable, for use on the move and in various environments. Various design aesthetics and product selections were considered when doing the actual fabrication and selection of material. The anticipated environment where the product could be used was considered. All mounting and fixing were well smoothened and anchored to the chassis that acted as a frame to the circuit board. Literature survey When we talk of amplifiers in most cases we refer to stereo workings or musical equipment. However this is a small depiction of the range of auditory amplifiers. Amplifiers are all over home and personal electronic devices like television, compact disk players, computer, public address systems and other devices that produce sound. Sound is an interesting occurrence. Whenever an object vibrates in the atmosphere, it moves the air particles about it. They in turn move the air particles about them, carrying the pulsation of the trembling throughout the air. Our ears accept these fluctuations in air pressure and interpret them into electrical signals the brain can process. Electronic sound equipment works the same basic way. It represents sound as a varying electric current. There are three steps in the sound production mechanism. Sound waves move a microphone diaphragm back and forth, and the microphone translates this movement into an electrical signal. The electrical signal fluctuates to represent the compressions and rarefactions of the sound wave. A recorder encodes this electrical signal as a pattern in some sort of medium -- as magnetic impulses on tape, for example, or as grooves in a record. A player re-interprets this model as an electrical signal and uses this current to move about a speaker cone back and forth. This re-creates the air-pressure fluctuations initially recorded by the microphone. It is evident that major components of these systems are in fact translators. They input the signal in one form and put it into another. In the end, the sound signal is translated back into its original form, a physical sound wave. ­ In order to record all of the minute pressure variations in a sound wave, the microphone diaphragm has to be exceptionally sensitive. This means it is very thin and moves only a short distance. As a result, the microphone produces a reasonably minute electrical current. This is well for most of the stages in the process as its strong enough to be used in the recorder, for example, and it is effortlessly transmitted through copper wires. However the last process that involves pushing the speaker cone backward and forward is extra difficult. To achieve this one will need to boost up the audio signal to increase its current at the same time preserving the same pattern of charge variation. This is the work of the amplifier. It basically produces an additionally powerful edition of the audio signal. This is the work of the amplifier. It basically produces an additionally powerful edition of the audio signal. In basic simple terms an amplifiers inputs a weak signal and power it up to create a signal that is powerful enough to vibrate the speakers. In reality though an amplifier creates new output signals related to the input signal. An easier way of understanding the amplifier is to take these two signals as two separate circuits. The output is generated by the power supply. The power supply gets its energy from a battery. The input signal on the other hand is the electrical audio signal that is recorded on a tape. In most amplifiers, this load is too much work for the original audio signal. For this reason, the signal is first boosted by a pre-amplifier, which sends a stronger output signal to the power amplifier. The pre-amplifier works the same basic way as the amplifier: The input circuit applies varying resistance to an output circuit generated by the power supply. Some amplifier systems use several pre-amplifiers to gradually build up to a high-voltage output signal. Methodology In this design project I have attempted to follow the standards and guidelines that all engineering products and devices are required to. I however have to state clearly being a student project resources and time were a challenge. It would therefore not compare to a commercial / industrial product. The design and development / and or manufacture followed the well known procedures for electronic products. First the concept was developed in class through guidance from faculty and reference from my course work. I reviewed all existing product and looked at variations and what new concept my new product would bring to the market or academia world if developed in a commercially and or industrial way. This followed with research into the product variation and specific pains that users experience and or advancement that are desirable for any use of the product. In this project I recognized that many challenges in product design and manufacture of amplifiers is on power and portability. Hence one of the key new features that this product introduces is portability. This being a student based project I did not have to work with government and industry agencies for standardization; however this would be a requirement in future if commercial productions are pursued. The next stage in my product development methodology was circuit design. I looked at all circuits that are capable of delivering the desired design. I a logical design of their functionality and model the expected output using electronic software, the circuit maker to simulate how they would work in real environment. It from this design that selection of ideal component were done. Each component was specifically reviewed and selected and previews of the physical fabrication including enclosures were developed. The cover selection including integrated displays, interface connectors and controls need to be thought about before any real bread board fabrication and circuit layout start. At the design part the electro-mechanical components and the housing of the key circuitry including the board outline and assembly are the drawn and imposed. Mechanical drawings are produced if the product has large electro-mechanical parts. In our case the mechanical part was simple and direct requiring no design at all. Following all those step is the layout of the graphics and numbering. This is normally applied in form of overlays, labels, silk screen and or a combination of all of them. In this project paper based labels were produced. Once all those steps have been completed the then the printed circuit layout start. This now and reorganizes the specific needs of the circuit diagram and the usage of electronic fabrication components with the desired form factor as required by enclosure and final product packaging. The completed printed circuit design is then processed on film etched onto printed circuit bread boards for the components assembler. Finally trial production and review of final product is done. Once the product has passed certain industry specifications and confirmation it is rolled out for mass production. At this point technical support team will be called upon to document the usability of the product based on user perception and reviews and guide the users on how to comfortably use the item. Results and discussion This circuit design was purposely done to produce broadcast media industry amplifiers with a microphone input. It however with little and or no modifications could be used in public theater and lecturer hall for public address system. The battery supply is a good compromise; the energy to power the fan stage could easily be obtained from a stander office electric fan. This way the input circuit is free from interference brought by main electricity supply. In circumstance where a stereo microphone will be used the circuit design will have to change and hence the scaling capability provided by two controls and a dual ganged- stereo potentiometer. At the same time low current is also used for convenience. The design of the circuit is used a low noise, high gain two stage PNP and NPN transistor amplifier, by means of direct current negative feedback through resister 6 to steady the operational setting accurately. Output intensity is attenuated by potentiometer one (p1) but, at the same time, the stage gain is reduced due to the improved value of resistor 5. This abnormal link of potentiometer 1 assists in getting a high headroom input, enabling it to maintain wide latitude of input sources. This is shown to be from 0.2 to 200 micro Volts root mean square for 1Volt root mean square output. AVID MC-1 Universal Multimedia Microphone Amplifier has the following specifications: Level control range: 10 decibel, Amplification for dynamic microphone: 46 decibel to 56 decibel, Amplification for electrets microphone: 16 decibel to 26 decibel. That amplifier is intended to increase the microphone level from various microphones to the level which is suitable for normal Personal Computer soundcard line level input. The circuit design uses a typical transistor amplifier with amplification of about 30 decibels to 40 decibels B. This however will depend on transistor used, existing environmental temperature and voltage. The dynamic microphone input is just a standard one transistor amplifier circuit with nothing special in it. Light emitting diode 1 is integrated into the circuit. This will light whenever the circuit is in operation. The voltage drop resulting from the Light emitting diode approximated as 1.8 volts has been taken care of in the design of the capacitor in Q1.Resistor R4 and capacitor C5 make a filter to filter out possible noise from battery or other power source which is used to feed this circuit. Capacitors C1, C2 and C3 are used to block the DC bias on Q1 base to flow out of microphone input to microphone. Conclusions The amplification factor in this circuit is determined mainly by the characteristics of charge Q1 and value of resistor R2. The circuit is designed for quite optimum performance but for modification purposes the value of resistor R1 TO values like 100 K ohms and 1 M ohm in order to achieve any significant performance. The project design and manufacturer was accomplished with a lot of efforts and though not all work and design in this was original many of the ideas were generated with a certain level of originality enabling convenience and effectiveness of the design. The circuit design and component descriptions are shown below Parts description: Potentiometer 1 2K2 Linear Potentiometer Resistors R1, R2, R3 100K 1/4W Resistors Resistor R4 8K2 1/4W Resistor Resistor R5 68R 1/4W Resistor Resistor R6 6K8 1/4W Resistor Resistor R7,R8 1K 1/4W Resistors Resistor R9 150R 1/4W Resistor Capacitor C1 1΅F 63V Polyester Capacitor Capacitors C2, C3, C4 100΅F 25V Electrolytic Capacitors Capacitor C5_____________22΅F 25V Electrolytic Capacitor Charge Q1___________BC560C 45V 100mA Low noise High gain PNP Transistor Charge Q2___________BC550C 45V 100mA Low noise High gain NPN Transistor Pin Jack J1_____________Jack socket (Mono 3 or 6 mm.) . REFERENCES Allen, J., Christie, A., Fithen, W., McHugh, A., Pickel, J. & Stoner, E. 1999, State of the Practice of Intrusion Detection Technologies [Online], Available: http://www.sei.cmu.edu/publications/documents/99.reports/99tr028/99tr028abstract.html , [Accessed 31 12 2009] Axelsson, S. 1998, Research in Intrusion-Detection Systems: A Survey [Online], Available: http://www.ce.chalmers.se/staff/sax, [Accessed 31 12 2009] Axelsson, S. 2000, Intrusion Detection Systems A Survey and Taxonomy [Online], Available: http://www.ce.chalmers.se/staff/sax/, [Accessed 31 12 2009] Bellovin, S., Leech, M. & Taylor, T. 2001, ICMP Traceback Messages [Online], Available: http://www.ietf.org/internet-drafts/draft-ietf-itrace-01.txt, [Accessed 31 12 2009] Carver, A., Hill, J., Surdu, J. & Pooch, U. 2000, ‘A Methodology for Using Intelligent Agents to provide Automated Intrusion Response’, Proceedings of the 2000 IEEE Workshop on Information and Security, United States Military Academy, West Point, NY, pp. 110-6 Cerf, V., Burleigh, S., Hooke, A., Turgerson, L., Durst, R., Scott, K. , Traveis, E. & Weiss, H. 2001, Interplanetary Internet (IPN): Architectural Definition [Online], Available: http://www.ietf.org/internet-drafts/draft-irtf-ipnrg-arch-00.txt, [Accessed 31 12 2009] CERT 2001, CERT/CC Statistics 1988-2001 [Online], Available: http://www.cert.org/stats/cert_stats.html, [Accessed 31 12 2009] Read More

This is the work of the amplifier. It basically produces an additionally powerful edition of the audio signal. In basic simple terms an amplifiers inputs a weak signal and power it up to create a signal that is powerful enough to vibrate the speakers. In reality though an amplifier creates new output signals related to the input signal. An easier way of understanding the amplifier is to take these two signals as two separate circuits. The output is generated by the power supply. The power supply gets its energy from a battery.

The input signal on the other hand is the electrical audio signal that is recorded on a tape. In most amplifiers, this load is too much work for the original audio signal. For this reason, the signal is first boosted by a pre-amplifier, which sends a stronger output signal to the power amplifier. The pre-amplifier works the same basic way as the amplifier: The input circuit applies varying resistance to an output circuit generated by the power supply. Some amplifier systems use several pre-amplifiers to gradually build up to a high-voltage output signal.

Methodology In this design project I have attempted to follow the standards and guidelines that all engineering products and devices are required to. I however have to state clearly being a student project resources and time were a challenge. It would therefore not compare to a commercial / industrial product. The design and development / and or manufacture followed the well known procedures for electronic products. First the concept was developed in class through guidance from faculty and reference from my course work.

I reviewed all existing product and looked at variations and what new concept my new product would bring to the market or academia world if developed in a commercially and or industrial way. This followed with research into the product variation and specific pains that users experience and or advancement that are desirable for any use of the product. In this project I recognized that many challenges in product design and manufacture of amplifiers is on power and portability. Hence one of the key new features that this product introduces is portability.

This being a student based project I did not have to work with government and industry agencies for standardization; however this would be a requirement in future if commercial productions are pursued. The next stage in my product development methodology was circuit design. I looked at all circuits that are capable of delivering the desired design. I a logical design of their functionality and model the expected output using electronic software, the circuit maker to simulate how they would work in real environment.

It from this design that selection of ideal component were done. Each component was specifically reviewed and selected and previews of the physical fabrication including enclosures were developed. The cover selection including integrated displays, interface connectors and controls need to be thought about before any real bread board fabrication and circuit layout start. At the design part the electro-mechanical components and the housing of the key circuitry including the board outline and assembly are the drawn and imposed.

Mechanical drawings are produced if the product has large electro-mechanical parts. In our case the mechanical part was simple and direct requiring no design at all. Following all those step is the layout of the graphics and numbering. This is normally applied in form of overlays, labels, silk screen and or a combination of all of them. In this project paper based labels were produced. Once all those steps have been completed the then the printed circuit layout start. This now and reorganizes the specific needs of the circuit diagram and the usage of electronic fabrication components with the desired form factor as required by enclosure and final product packaging.

The completed printed circuit design is then processed on film etched onto printed circuit bread boards for the components assembler.

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