Single Stage Common Emitter Amplifier
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What is one of the main advantages of a single stage CE amplifier?

  • It has a very narrow frequency response.
  • It is the least expensive amplifier. (correct)
  • It can serve as a final stage of amplification.
  • It can provide high power output.

    • Which of the following is a disadvantage of a single stage CE amplifier?

  • It can be noisy with age. (correct)
  • It provides good impedance matching.
  • It has low amplitude distortion.
  • It has high audio fidelity.

    • What application is a single stage CE amplifier commonly used for?

  • In high-frequency RF applications.
  • In radio and television receivers. (correct)
  • As the final stage in an audio system.
  • As a power amplifier.

    • What process involves connecting the output of one amplifier stage to the input of another?

    <p>Cascade</p> Signup and view all the answers

    What is a major limitation of single stage CE amplifiers at low and high frequencies?

    <p>They exhibit reduced voltage gain.</p> Signup and view all the answers

    What type of distortion does a single stage CE amplifier typically have?

    <p>Low amplitude distortion.</p> Signup and view all the answers

    In which of the following scenarios would a single stage CE amplifier be the least suitable choice?

    <p>When used as a final stage of amplification.</p> Signup and view all the answers

    Which type of amplifier is typically used when the output of a single stage amplifier is insufficient?

    <p>Multi-stage transistor amplifier.</p> Signup and view all the answers

    What is a key feature of a double tuned amplifier compared to a single tuned amplifier?

    <p>It comprises two inductively coupled tuned circuits.</p> Signup and view all the answers

    Which components are part of the double tuned amplifier's construction?

    <p>Two tuned circuits with specified resistors.</p> Signup and view all the answers

    Where is the signal to be amplified applied in a double tuned amplifier?

    <p>At the input terminal through a coupling capacitor.</p> Signup and view all the answers

    What must be adjusted to match the resonant frequency of the input signal in a double tuned amplifier?

    <p>The values of L1 or C1.</p> Signup and view all the answers

    What role do the resistors R1, R2, and RE serve in the double tuned amplifier?

    <p>To provide necessary d.c. currents and voltages.</p> Signup and view all the answers

    How does the output from the tuned circuit L1C1 interact with L2C2 in a double tuned amplifier?

    <p>L1C1's output is inductively coupled to L2C2.</p> Signup and view all the answers

    In which application are double tuned circuits primarily used?

    <p>In radio and television receivers for coupling various circuits.</p> Signup and view all the answers

    What is the significance of having a high impedance in the tuned circuit L1C1?

    <p>It facilitates a large output voltage across the tuned circuit.</p> Signup and view all the answers

    What is the primary purpose of a coupling device in a multistage amplifier?

    <p>To transfer AC while blocking DC between stages</p> Signup and view all the answers

    How is the overall gain of a multistage amplifier calculated?

    <p>By multiplying the voltage gains of individual stages</p> Signup and view all the answers

    Which type of coupling is NOT mentioned as a method for connecting stages in a multistage amplifier?

    <p>Inductive Coupling</p> Signup and view all the answers

    What electrical component in the two-stage amplifier circuit helps to stabilize the biasing?

    <p>Potential divider network</p> Signup and view all the answers

    In terms of voltage gain in decibels, how is the overall voltage gain expressed?

    <p>Gv = Gv1 + Gv2</p> Signup and view all the answers

    What does the biasing circuit in a single stage common emitter amplifier primarily do?

    <p>Stabilizes the operating point of the transistor</p> Signup and view all the answers

    What is the purpose of the coupling capacitor Cc1 in the circuit?

    <p>To allow only a.c. signals to flow</p> Signup and view all the answers

    Which statement about the emitter bypass capacitor in a two-stage amplifier is true?

    <p>It provides a low reactance path to the signal.</p> Signup and view all the answers

    What is the role of the common power supply VCC in a two-stage amplifier circuit?

    <p>To provide power for the biasing network</p> Signup and view all the answers

    What would happen if the emitter bypass capacitor CE is not used?

    <p>The output voltage may shift due to a voltage drop</p> Signup and view all the answers

    In the context of a common emitter amplifier, what does the relationship $I_C = \beta I_B$ signify?

    <p>The collector current is amplified by the transistor's gain</p> Signup and view all the answers

    In a multistage amplifier, what happens to the overall gain as the number of stages increases?

    <p>The overall gain increases as the product of the individual stage gains</p> Signup and view all the answers

    How does the output phase of a single stage CE amplifier relate to its input?

    <p>It is 180° out of phase with the input</p> Signup and view all the answers

    What is the characteristic behavior of a series resonant circuit at its resonant frequency?

    <p>It offers low impedance, allowing high current.</p> Signup and view all the answers

    What is the primary function of the coupling capacitor Cc2 in the amplifier circuit?

    <p>To allow only the amplified a.c. signal to flow to the output</p> Signup and view all the answers

    In a parallel tuned circuit, what happens to the inductive and capacitive reactance as the frequency increases?

    <p>Inductive reactance increases while capacitive reactance decreases.</p> Signup and view all the answers

    Which of the following is NOT a component of the biasing circuit in a single stage common emitter amplifier?

    <p>C1</p> Signup and view all the answers

    In a single stage common emitter amplifier, what is the effect of increasing the resistor RC on the circuit's output?

    <p>It will increase the output voltage swing</p> Signup and view all the answers

    What defines the resonance frequency in a parallel tuned circuit?

    <p>When the inductive and capacitive reactance are equal.</p> Signup and view all the answers

    What happens to the impedance of a parallel tuned circuit at resonance?

    <p>It is maximum and defined as Zp = L/CR.</p> Signup and view all the answers

    In the resonance curve for a parallel tuned circuit, how does impedance change as frequency moves away from resonance?

    <p>Impedance decreases rapidly.</p> Signup and view all the answers

    What is the main component difference between a series resonant circuit and a parallel resonant circuit?

    <p>Series circuits connect inductor and capacitor in series; parallel circuits connect them in parallel.</p> Signup and view all the answers

    Which of the following statements is true regarding the behavior of a parallel tuned circuit as frequency approaches resonance?

    <p>The circuit allows maximum current to flow.</p> Signup and view all the answers

    What role does the supply source frequency play in a parallel resonant circuit?

    <p>It determines the impedance and behavior at resonance.</p> Signup and view all the answers

    Study Notes

    Single Stage Common Emitter Amplifier

    • A single stage amplifier is a simple amplifier using a single transistor with associated circuitry.
    • This type of amplifier amplifies weak signals.
    • They are often used as the first stage of larger, multi-stage amplifiers.

    Construction of a Single Stage Common Emitter Amplifier

    • The biasing and stabilisation circuit is composed of resistors R1, R2 and RE.
    • The input capacitance, Cc1, couples the signal to the base of the transistor.
    • This input capacitance prevents the signal source resistance from affecting the bias.
    • The emitter bypass capacitor, CE, allows the amplified AC signal to flow with minimal resistance.
    • The coupling capacitor, Cc2, allows only the amplified AC signal to flow, coupling it to the output device.

    How a Single Stage Common Emitter Amplifier Works

    • A small amount of base current flows when the weak input signal is applied.
    • This base current controls a much larger collector current, resulting in an amplified output.
    • The transistor action amplifies the collector current, which is beta times the base current.
    • This amplification leads to a significant voltage drop across the resistor RC which is collected as the output.
    • The output is 180 degrees out of phase with the input signal.

    Frequency Response of Single Stage CE Amplifier

    • The frequency response is a measure of how the gain of the amplifier varies with the frequency of the input signal.
    • The gain of a single-stage CE amplifier is typically highest at a certain frequency (the resonant frequency) and decreases as the frequency deviates from this point.

    Advantages of a Single Stage CE Amplifier

    • Wide frequency response and high bandwidth.
    • Cost-effective and convenient to build.
    • High audio fidelity.
    • Low amplitude and frequency distortion.

    Disadvantages of a Single Stage CE Amplifier

    • Can become noisy over time, particularly in humid climates.
    • Voltage gain decreases at both low and high frequencies.
    • Poor impedance matching prevents it from being used as a final stage in an amplifier.

    Applications of a Single Stage CE Amplifier

    • Used in the initial stages of public address (PA) systems.
    • Used in stereo amplifiers.
    • Used as a voltage amplifier in various devices.
    • Also used in tape recorders, CD players, VCRs, DVD players, radio and television receivers.

    Multi-Stage Amplifiers

    • Multi-stage amplifiers use multiple stages to increase the amplification of a signal.
    • Each stage consists of a transistor and its associated circuitry.
    • The output of one stage is coupled to the input of the next stage using coupling devices.
    • This process of joining two amplifier stages is called cascading.

    Purpose of the Coupling Device in Multi-Stage Amplifiers

    • To transfer the amplified AC signal from one stage to the next.
    • To prevent DC signals from passing from one stage to the next, ensuring isolation between stages.

    Multistage Amplifier Gain

    • Overall voltage gain is the product of the gains of each individual stage.
    • Overall voltage gain expressed in decibels (dB) is the sum of the gains of each individual stage in dB.

    Types of Coupling in Multistage Amplifiers

    • Resistance-capacitance coupling (RC coupling)
    • Transformer coupling
    • Direct coupling

    Two-Stage RC Coupled Amplifier

    • Uses two transistors in the common emitter (CE) configuration.
    • A common power supply, VCC, is used for both transistors.
    • Resistors R1, R2 and RE provide bias and stabilisation.
    • CE is an emitter bypass capacitor providing a low reactance path for the signal.

    Series Tuned Circuit

    • Consists of an inductor (L) and a capacitor (C) connected in series.
    • At resonant frequency, the circuit offers low impedance, allowing high current to flow.
    • Impedance increases significantly at frequencies far from the resonant frequency.

    Parallel Tuned Circuit

    • Consists of an inductor (L) and a capacitor (C) connected in parallel.
    • It offers high impedance at the resonant frequency.
    • The impedance decreases significantly at frequencies far from the resonant frequency.

    Resonant Frequency

    • The resonant frequency of a tuned circuit is the frequency at which the inductive reactance and capacitive reactance are equal.

    Double Tuned Amplifier

    • Uses two tuned circuits connected in tandem to overcome the limitations of single-tuned amplifiers.
    • One tuned circuit, L1C1, acts as the collector load and the other, L2C2, acts as the output.

    Construction of a Double Tuned Amplifier

    • Consists of a transistor amplifier with two tuned circuits (L1C1 and L2C2).
    • The tuned circuits are inductively coupled to each other.
    • Resistors R1, R2 and RE provide bias and stabilisation for the transistor.

    Operation of a Double Tuned Amplifier

    • The signal is applied to the input terminal through the coupling capacitor Cin.
    • The resonant frequency of the L1C1 tuned circuit is adjusted to match the signal frequency.
    • This tuned circuit offers high impedance to the signal, leading to a large output across it.
    • The output from L1C1 is inductively coupled to the L2C2 tuned circuit.
    • Double tuned circuits are commonly used in radio and television receivers.

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    Description

    Explore the fundamentals of single stage common emitter amplifiers through this quiz. Learn about their construction, operation, and the key components that contribute to their function as signal amplifiers. This quiz is essential for understanding basic amplifier circuitry.

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