CBSE Class 12-science Physics Semiconductor Electronics
- 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?
- 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.
- 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.
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