If the common emitter current gain β∞ of the transistor used in the amplifier circuit shown is 200, What will the quiescent base current be equal to if the quiescent emitter current is 1 mA.
Asked by Topperlearning User | 10th Jul, 2014, 02:06: PM
In the common emitter mode, the current amplification factor (current gain) under no signal condition (βdc) is given by
βdc = IC/IB where IC is the collector current and IB is the base current (both under no signal conditions).
Since the collector current is almost equal to the emitter current IE (because of large value of βdc), we have
βdc ≈ IE/IB
Therefore IB ≈ IE/βdc =1 mA/200 = 0.005 mA = 5μA
Answered by | 10th Jul, 2014, 04:06: PM
- Current amplifier
- Draw a circuit diagram for use of NPN transistor as an amplifier in common emitter configuration. The input resistance of a transistor is 1000 Ω. On changing its base current bv 10 uA. the collector current increases bv 2 mA. If a load resistance of 5 k Ω is used in the circuit, calculate: (i) The current gain (ii) Voltage gain of the amplifier
- Explain how the input and output voltages are out of phase by 180o for a common-emitter transistor amplifier.
- For an n-p-n transistor in the common-emitter configuration, draw a labelled circuit diagram of an arrangement for measuring the collector current as a function of collector-emitter voltage for at least two different values of base current. Draw the shape of the curves obtained. Define the terms:(i) output resistance and (ii) 'current amplification factor'.
- The adjoining figure shows a common emitter transistor amplifier which uses a silicon transistor. If the quiescent emitter current is 1 mA what is the base biasing voltage?
- For a common emitter amplifier, the audio signal voltage across collector resistance 2 kΩ is 2V. If the current amplification factor of the transistor is 200 and base resistance is 1.5Ω, the input signal voltage and base current are
- A common emitter low_frequency amplifier has an effective input resistance of 1 kΩ. The collector load resistance is 5 kΩ. On applying a signal, the_base current changes by 10 μA and the collector current changes by 1 mA. what is the power gain of this amplifier?
- A transistor amplifier circuit is operated with an emitter current of 2 mA. The collector current is 1.98 mA. What is the common emitter current gain (β2dc) of the transistor used in the circuit?
- Illustrate the cut off, active, and saturation regions on a plot of V0 and Vi for a transistor switch circuit.
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number