04-01-2013, 04:38 PM
MEASUREMENT OF PARAMETERS OF EMITTER
FOLLOWER AND SOURCE FOLLOWER
[attachment=46533]
THEORY: EMITTER FOLLOWER
The common collector circuit is also known as emitter follower. The ac output voltage
from a CC circuit is essentially the same as the input voltage; there is no voltage gain or
phase shift. Thus, the CC circuit can be said to have a voltage gain of 1. The fact that the CC
output voltage follows the changes in signal voltage gives the circuit its other name emitter
follower. The input impedance of a CC amplifier is high. Output impedance is low and the
EC-I Lab Manual EC-261
BAPATLA ENGINEERING COLLEGE (Autonomous):: BAPATLA
Voltage gain is almost unity. Because of these Characteristics the CC circuit is normally
used as a buffer amplifier, placed between a high impedance signal source and a low
impedance load
SOURCE FOLLOWER
The FET common drain circuit has the output voltage developed across the source resistor
Rs. Here the ac output voltage is closely equal to the ac input voltage, and the circuit can be
said to have unity gain. Because the output voltage at the source terminal follows the signal
voltage at the gate, the common drain circuit is also known as a source follower.
A common drain circuit has a voltage gain approximately equal to 1, no phase shift
between input and output, very high input impedance and low output impedance. Because of
its high Zi, low Zo and unity gain the CD circuit is used as a buffer amplifier between a high
impedance signal source and a low impedance load.
FOLLOWER AND SOURCE FOLLOWER
[attachment=46533]
THEORY: EMITTER FOLLOWER
The common collector circuit is also known as emitter follower. The ac output voltage
from a CC circuit is essentially the same as the input voltage; there is no voltage gain or
phase shift. Thus, the CC circuit can be said to have a voltage gain of 1. The fact that the CC
output voltage follows the changes in signal voltage gives the circuit its other name emitter
follower. The input impedance of a CC amplifier is high. Output impedance is low and the
EC-I Lab Manual EC-261
BAPATLA ENGINEERING COLLEGE (Autonomous):: BAPATLA
Voltage gain is almost unity. Because of these Characteristics the CC circuit is normally
used as a buffer amplifier, placed between a high impedance signal source and a low
impedance load
SOURCE FOLLOWER
The FET common drain circuit has the output voltage developed across the source resistor
Rs. Here the ac output voltage is closely equal to the ac input voltage, and the circuit can be
said to have unity gain. Because the output voltage at the source terminal follows the signal
voltage at the gate, the common drain circuit is also known as a source follower.
A common drain circuit has a voltage gain approximately equal to 1, no phase shift
between input and output, very high input impedance and low output impedance. Because of
its high Zi, low Zo and unity gain the CD circuit is used as a buffer amplifier between a high
impedance signal source and a low impedance load.