semiconductor DEE20023

semiconductor DEE20023. MUHAMMAD RAIDZ HADZIQIN BIN RAMLI 13DEE21F1052.

JFET AMPLIFIER CONFIGURATION. COMMON SOURCE AMPLIFIER COMMON DRAIN AMPLIFIER.

The common-source (CS) amplifier may be viewed as a transconductance amplifier or as a voltage amplifier..

As a transconductance amplifier, the input voltage is seen as modulating the current going to the load. As a voltage amplifier, input voltage modulates the amount of current flowing through the FET, changing the voltage across the output resistance according to Ohm's law. FET device's output resistance typically is not high enough for a reasonable transconductance amplifier (ideally infinite), nor low enough for a decent voltage amplifier (ideally zero)..

Also known as a source follower , typically used as a voltage buffer. In this circuit the gate terminal of the transistor serves as the input, the source is the output, and the drain is common to both (input and output), hence its name..

In addition, this circuit is used to transform impedances. For example, the Thévenin resistance of a combination of a voltage follower driven by a voltage source with high Thévenin resistance is reduced to only the output resistance of the voltage follower, a small resistance. That resistance reduction makes the combination a more ideal voltage source. Conversely, a voltage follower inserted between a driving stage and a high load ( ie a low resistance) presents an infinite resistance (low load) to the driving stage, an advantage in coupling a voltage signal to a large load..

Typically used as a current buffer or voltage amplifier. In this circuit the source terminal of the transistor serves as the input, the drain is the output and the gate is common to both..

This configuration is used less often than the common source or source follower. Usually used in CMOS RF receivers for ease of impedance matching and potentially has lower noise..