The document provides instructions for constructing and analyzing a common collector (CC) amplifier circuit using a BJT transistor. The CC amplifier has a large current gain. Learners will build the circuit in a simulation with a 2N2222 transistor, 5.1K load resistor, function generator for a 1.5V, 2KHz sine wave input, and voltmeters to measure the input and output. Running time and frequency domain simulations will allow the learner to observe the output following the input signal with the same amplitude but a downward shifted DC level due to the BJT's VBE drop.

1. Access this lab-manual at:
http://www.docircuits.com/lab-manual/23/common-collector-amplifier
Common Collector Amplifier
Aim
The aim is to
1. Understand the function of a Common Collector
Amplifier
2. Construct a Common Collector Amplifier
3. Perform AC and DC Analysis on a CC Amplifier
4. Apply the concept to Regulators
Related Experiments
COMMON COLLECTOR
Description
Theory:
It is called the common collector configuration because (ignoring the power supply battery) both the signal source
and the load share the collector lead as a common connection point as in the figure.
¨It should be apparent that the load resistor in the common-collector amplifier circuit receives both the base
and collector currents, being placed in series with the emitter.
¨Since the emitter lead of a transistor is the one handling the most current, it would be reasonable to
presume that this amplifier will have a very large current gain.
¨This presumption is indeed correct: the current gain for a common-collector amplifier is quite large, larger
than any other transistor amplifier configuration.
¨Construct the circuit as shown by dragging a 2N2222 BJT npn transistor, load resistor of 5.11 KΩ
¨Drag and drop 1 function generator, 1 DC Source and 2 DC voltmeters. Connect the circuit as shown.
¨Click on DCSource1 and provide 15V to it.
¨Click on Function generator. Provide Sine wave of 1.5V and 2 KHz.
BJT
AMPLIFIER

2. ¨Click on Function generator. Provide Sine wave of 1.5V and 2 KHz.
¨Give Offset ( Bias ) of 2.3V.
¨Run Simulation ( Time Domain )
¨Click on Analyse to view results
¨Plot Oscilloscope over time
Conclusion
¨We can see that the output follows the input.
¨The output is the same peak-to-peak amplitude as the input. Though, the DC level is shifted downward by
one VBE diode drop.