Working of an amplifer
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The document discusses amplifiers, their components, types, and applications, highlighting their role in increasing signal power. It details various amplifier classes (A, B, AB, C) and the characteristics of operational amplifiers, along with their functions in mathematical operations on voltage signals. Additionally, it covers practical uses of amplifiers in devices such as powered speakers and sound reinforcement systems.
Working of an amplifer
- 1. GROUP MEMBER’S: Zeeshan Shabbir M. Bilal Fiaz Ashraf Talha Zameer Umair Ali Hammad Hassan
- 2. 1. AMPLIFIER 2. PARTS OF AMPLIFIER 3. AMPLIFIER TYPES 4. OPERATIONAL AMPLIFIER 5. CLASSES OF AMPLIFIER 6. ADVANTAGES OF AMPLIFIER 7. USES OF AMPLIFIER
- 3. 1. AMPLIFIER………………………………………………………Zeeshan Shabbir 2. PARTS OF AMPLIFIER…………………………………………..M. Bilal 3. AMPLIFIER TYPES……………………………………………...FiazAshraf 4. OPERATIONAL AMPLIFIER……………………………………Talha Zameer 5. CLASSES OF AMPLIFIER…………………………………….…UmairAli 6. ADVANTAGES OF AMPLIFIER…………………………………Hammad Hassan 7. USES OF AMPLIFIER……………………………………....................................
- 5. An Amplifier is an electronic device that increases the power of a signal. It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude. In this sense, an amplifier modulates the output of the power supply. The output signal is more than input signal.
- 6. The amplification process is similar to the way in which the human receives the sound from our surrounding. Sound waves will be sent through a microphone. The diaphragm of the microphone moves it in a peculiar motion and converts it into electrical signals. This fluctuating electric signal will be represented as compressions and rarefactions of the original sound. The electric signal will be encoded by the recorder and stored in a tape, CD and so on.
- 8. Step 1: In this setup the amplifier’s output circuit is connected to the emitter & the collector. The output circuit connects to the emitter & the base. Step 2: When no current flow through the input circuit, free electrons from the n-type material fill the available holes in the p-type material. Step 3: This create depletion zone (area where current can’t flow easily) at the boundaries bw the n-type layers & the p-type layers. Step 4: When current flows across the input circuit, it cause an extra voltage boost at the base electrode. This gets electrons moving again, shrinking the depletion zone. Electrical resistance drops & electrons can move from the emitter to the collector again. In this way the voltage at the base electrode determines the overall resistance of the transistor & therefore the current in the output signal.
- 9. M. Bilal
- 11. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. NPN Transistor: PNP Transistor:
- 12. A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.
- 13. The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction).
- 14. Fiaz Ashraf
- 15. The four basic types of amplifiers are as follows: Voltage amplifier: Current amplifier: Transconductance amplifier: Transresistance amplifier:
- 16. Voltage amplifier: This is the most common type of amplifier. An input voltage is amplified to a larger output voltage. The amplifier's input impedance is high and the output impedance is low.
- 17. Current amplifier: This amplifier changes an input current to a larger output current. The amplifier's input impedance is low and the output impedance is high.
- 18. Transconductance amplifier: This amplifier responds to a changing input voltage by delivering a related changing output current.
- 19. Transresistance amplifier: This amplifier responds to a changing input current by delivering a related changing output voltage. Other names for the device are transimpedance amplifier and current-to-voltage converter.
- 20. Talha Zameer
- 21. Operational amplifiers can be used to perform mathematical operations on voltage signals such as inversion, addition, subtraction, integration, differentiation, and multiplication by a constant. Operational amplifier is used to amplify DC and AC signals.
- 22. Negative Feedback is the process of "feeding back" a fraction of the output signal back to the input, but to make the feedback negative, we must feed it back to the negative or "inverting input" terminal of the op-amp using an external Feedback Resistor called Rƒ. This feedback connection between the output and the inverting input terminal forces the differential input voltage towards zero This effect produces a closed loop circuit to the amplifier resulting in the gain of the amplifier now being called its Closed-loop Gain.
- 23. + - VL Gain (A) RL Rs Vs Source Amplifier load Ideally the output voltage is amplified version of the source or VL = A. Vs
- 24. Umair Ali
- 25. Amplifier Classes is the term used to differentiate between the different amplifier types. The most commonly constructed amplifier classes are those that are used as audio amplifiers, mainly class A, B, AB and C and to keep things simple, it is these types of amplifier classes we will look at here in more detail.
- 26. Class A Class B Class AB Class C
- 27. 100% of the input signal is used (conduction angle Θ = 360°). The active element remains conducting all of the time.
- 28. 50% of the input signal is used (Θ = 180°); the active element carries current half of each cycle, and is turned off for the other half.
- 29. As its name suggests, the Class AB Amplifier is a combination of the “Class A” and the “Class B” type amplifiers Class AB is intermediate between class A and B, the two active elements conduct more than half of the time.
- 30. A class C amplifier conducts for less than 180. Class C amplifiers are used extensively in radio communications circuits.
- 31. Hammad Hassan
- 32. Despite the complexity involved, a properly designed class D amplifier offers the following benefits: ◦ Reduction in size and weight of the amplifier, ◦ Reduced power waste as heat dissipation and hence smaller (or no) heat sinks, ◦ Reduction in cost due to smaller heat sink and compact circuitry, ◦ Very high power conversion efficiency, usually above 90% above one quarter of the amplifier's maximum power, and around 50% at low power levels.
- 34. Mobile phones: The internal loudspeaker is driven by up to 1 W.
- 35. Powered speakers: Powered speakers, also known as self-powered speakers and active speakers, are loudspeakers that have built-in amplifiers.
- 36. High-end audio:
- 37. Bass amplifiers: Bass instrument amplification, used for the bass guitar, double bass and similar instruments.
- 38. Sound Reinforcement: A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience
- 39. Active subwoofers: A subwoofer (or sub) is a woofer, or a complete loudspeaker, which is dedicated to the reproduction of low-pitched audio frequencies known as bass.