Question

3.2 14 marks] You are required to design, set up and physically measure the voltage gain of a BJT based CE amplifier with (Emitter resistance bypassed) with Emitter Stabilized Bias scheme with an external load resistance RL (This question is independent, do not mix with question 3.1) a) Draw the schematic diagram of the set up you are contemplating for this experiment. b) To set up the experiment, what all the components (such as resistors etc.) and lab equipment are needed (such as Oscilloscope). Also, think of your experiments in the previous labs, and identify clearly the name of each component in the circuit you have drawn for part (a) (for example, Oscilloscope: Tektronix 2213A). For the ones that are not marked/named, list them (such as probes, breadboard, etc.). o) Explain briefly, the procedure for how you would measure the voltage gain of the above amplifer, based on the above set up.

Answer 1

Answer:

b) From the above circuit we are able to specify the come components required for the experiment. DC power supply ( biasing) Function generator (sinusoidal waveform) Oscilloscope ( observe waveforms and their values) Resistors ( RB,Rc,RL,RE) Capacitors ( Cc,Ce,Cb) Breadboard Connection Wires Probes Multimeter ( To check terminals of BJT, DC parameters) BJT c) To measure the voltage gain we needed to determine the output voltage corresponding to input voltage as voltage gain is defined as the ratio of output AC voltage to the input voltage. Initially, set all the DC parameters i.e bias the circuit and set the question -point. Apply an sinusoidal input from the function generator of certain voltage, frequency and observe the output voltage in the oscilloscope. Computer the voltage gain at this frequency. In BJT the voltage gain depends on the frequency and it is maximum in the mid band. So, Increase the frequency keeping the input voltage constant and again check the output voltage and compute voltage gain. Tabulate the readings for various frequencies and compute the voltage gain. Finally, select the mid band gain which corresponds to maximum voltage gain